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Mustad Hooks – 3670

Mustad-Limerick Hooks hook silhouette
Hook Reference › O. Mustad & Son Hooks › Mustad Hooks – 3670

O. Mustad & Son 3670

Mustad-Limerick Hooks1925 or later; exact production span not established

Evidence reviewed October 26, 2026. Marks: P photographically · V verified · I inferred · E estimated · S speculative What they mean

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Summary

Mustad Quality 3670 is factory-labeled “Mustad-Limerick Hooks” and “Hollow Point.” The fully legible Key Brand box documents 100 black hooks in No. 8 with a “T. up tap. eye” P.

Photographic record

8 photographs

Faded Mustad Quality 3670 Key Brand box label.
IMG-1Mustad 3670 Box1 Faded Key Brand packaging for Mustad Quality 3670, showing heavy label wear and edge abrasion (P).

How to identify it

Identify Quality 3670 by the factory wording “Mustad-Limerick Hooks,” “Hollow Point,” and “T. up tap. eye Black” on Key Brand packaging P. The photographed size 8 box also states “100” and “No. 8.” The hook itself has a turned-up tapered eye and concave inner point face P. A purple handwritten “12” on V1 is not a verified factory size marking.

Technical profile and measurements

Features of the model, as recorded
FeatureRecordedEvidence
EyeTapered Eye, Turned Up
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Turned-up tapered eye with an elongated closure; no long return leg runs parallel to the shank P.

LBL-1LBL-5OBS-1OBS-8SRC-1
WireStandardCMP-3IMG-3IMG-4IMG-6IMG-7CMP-3 compared with 214 catalogued hooks classified Standard
ShankStandard — PlainCMP-1OBS-5OBS-12CMP-1 compared with 201 catalogued hooks classified Standard
BendLimerick
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Factory packaging names the pattern Mustad-Limerick Hooks; photographs show a deep rounded bend with a distinct transition into the shank P.

LBL-1LBL-5SRC-1CMP-2IMG-3IMG-7IMG-8OBS-2OBS-9CMP-2 compared with 80 catalogued hooks classified Limerick, near the line with Sproat
PointHollow Point
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Single triangular barb positioned close to the point P.

LBL-1LBL-5OBS-3OBS-10OBS-4OBS-11
FinishBlack Japanned — judged from the photographs
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Factory packaging states Black; photographs show a glossy black coating. A specialist dealer describes the finish as Japanned PV.

LBL-1LBL-5OBS-6OBS-13SRC-5

The photographed hooks have a straight plain shank, a deep Limerick bend, a turned-up tapered eye, and a long point with a concave inner face P. The factory box explicitly states “Hollow Point” and “Black” P. Catalog-wide silhouette comparison places the shank proportion in the Standard category and the wire thickness in Standard wire (CMP-1, CMP-3).

Measurements

Per size, with how each dimension was taken
SizeOverall lengthShank lengthGap widthBend depthWire diameterWeight
6Specimen S323.5 mm EcaliperMEA-515.2 mm EcaliperMEA-6—8.4 mm EcaliperMEA-70.76 mm EcaliperMEA-8—
8Specimen S219 mm EcaliperMEA-112.2 mm EcaliperMEA-2—6.6 mm EcaliperMEA-30.76 mm EcaliperMEA-4—
Calibrated SVG True-scale preview

How hook dimensions are measuredA hook outline with dimension lines for overall length, shank length, gap, bend depth, and wire diameter.Overall lengthShank lengthGapBend depthWire diameter
Overall length
Eye to the farthest point of the bend.
Shank length
Eye to the start of the bend.
Gap
Point to shank, at right angles to the shank.
Bend depth
Shank to the bottom of the bend.
Wire diameter
Across the wire, measured by caliper where possible.
Catalog records. Physical measurements are recorded for S2 size 8 and S3 size 6. S1 has only a proposed grid-derived overall length.

Specimens, packaging, and label

This record documents 3 specimens. Each describes itself only; none stands for every example of the model.

Faded Mustad Quality 3670 Key Brand box label.
Open full size
Mustad Quality 3670 box with faded label and handwritten 12.
Open full size

S1 · Boxed specimen, size not established

Container
Box
Hook condition
Glossy black coating largely intact with small surface specks and irregularities; no obvious red rust is visible in the supplied views.
Packaging condition
Fair — significant wear, partially legible
Wear
label and box edges: Printing is strongly faded and abraded; box edges show wear, creasing, and small tears. LBL-4
Photographs
IMG-1IMG-2IMG-3IMG-4

Two associated hooks share the same general silhouette. A proposed grid-derived overall length is about 12.8 mm, but the hook size is not established.

What the label says

LBL-1 printed · paper label, product text from IMG-1IMG-2
O. MUSTAD & SO[?]
Manufacturers
OSLO - NORWAY
Qual. 3670
Hollo[?] Point
Mustad-Limerick Hoo[?][?]
100    T. up tap. eye Blac[?]
No. [?]    Made in Norw[?][?]
LBL-2 trademark · label, left column from IMG-2
Key
Brand
LBL-3 handwritten · label face, lower center near No. line from IMG-2
12
Trademark
Skeleton-key device between the words Key and Brand; decorative flower-like border.
As entered on the specimen record
O. MUSTAD & SO[?]
Manufacturers
OSLO - NORWAY
Qual. 3670
Hollo[?] Point
Mustad-Limerick Hoo[?][?]
100    T. up tap. eye Blac[?]
No. [?]    Made in Norw[?][?]
Key
Brand
Layout
Product text occupies the main paper label; Key Brand trademark text and skeleton-key device appear in the left column within a decorative flower-like border.
Later marks
Purple handwritten “12” near the lower center of the label; meaning unknown.
Mustad Quality 3670 No. 8 Key Brand box label.
Open full size

S2 · Boxed No. 8 specimen

Size
8 (printed on the label)
Container
Box
Hook condition
Glossy black coating substantially intact with small specks, abrasions, and surface irregularities visible in close-up.
Packaging condition
Very Good — light wear, fully legible
Wear
box edges and lower flap: Minor edge wear and light toning; lower flap is slightly bowed or open. LBL-7
Measured
size 8
Photographs
IMG-5IMG-6IMG-7IMG-8

Factory label documents No. 8 and quantity 100. Physical-caliper records give 19.04 mm overall length, 12.192 mm shank length, 6.604 mm bend depth, and 0.762 mm wire diameter.

What the label says

LBL-5 printed · front label, product text from IMG-5
O. MUSTAD & SON
Manufacturers
Oslo - Norway
Qual. 3670
Hollow Point
Mustad-Limerick Hooks
100    T. up tap. eye Black
No. 8    Made in Norway
LBL-6 trademark · front label, left column from IMG-5
KEY
BRAND
Trademark
Skeleton-key device between KEY and BRAND; decorative flower-like border.
As entered on the specimen record
O. MUSTAD & SON
Manufacturers
Oslo - Norway
Qual. 3670
Hollow Point
Mustad-Limerick Hooks
100    T. up tap. eye Black
No. 8    Made in Norway
KEY
BRAND
Layout
Main product text is printed to the right of the Key Brand skeleton-key device within a decorative flower-like border.

S3 · Recorded size 6 specimen

Size
6 (from the existing record)
Container
Other
Measured
size 6

Carried physical-caliper record: 23.46 mm overall length, 15.24 mm shank length, 8.382 mm bend depth, and 0.762 mm wire diameter. No specimen image or package is associated with this record in the checked evidence.

Condition

Hook coatings are substantially intact with small specks and surface irregularities. V1 packaging is faded and worn; V2 has light edge wear P.

Pattern history and manufacturer context

Series

The checked evidence does not establish the first or last catalog appearance of Quality 3670. Factory packaging confirms the 3670 designation and Key Brand presentation, while the Oslo address places the photographed packaging in 1925 or later PV.

Design lineage

The factory product name identifies the model as a Limerick pattern P, and FlyHooks.org independently classifies its bend as Limerick V. The checked record does not establish a specific predecessor, successor, or manufacturer-to-manufacturer design lineage.

Dating

Both photographed labels use Oslo - Norway. The city officially adopted the name Oslo on 1 January 1925 V; the checked evidence does not establish the model's first or last production year.

O. Mustad & Son — The photographed boxes use the address Oslo - Norway, placing this packaging no earlier than 1925, when the city officially adopted the name Oslo V. Read the maker’s history →

Use

  • Nymph
  • Streamer / bucktail
  • Salmon
  • Sea trout

Primary application

FlyHooks.org lists the 3670 for streamer, nymph, salmon, trout, freshwater, and sea-trout use V. The factory labels in the photographed specimens do not state an intended fishing application.

Other uses

FlyHooks.org lists streamer, nymph, salmon, trout, freshwater, and sea-trout uses for the 3670 V.

Collecting and buying

2.5 / 10CollectabilityRarity: Common

2.5/10 — Common, with interest. Current evidence shows active marketplace and specialist-dealer offerings, but no production totals, sold-frequency evidence, or documented scarcity supports a higher band I.

Basis: Two current asking sources show the model in active commerce, but the checked evidence contains no production totals, surviving-example count, or completed-sale frequency establishing scarcity.

Two current asking sources show Quality 3670 in active commerce, including a size 8 box of 100 hooks at $17.99 and a specialist dealer offering at the same asking price V. Neither source records a completed sale, and the checked evidence provides no production totals or documented scarcity.

Under the site rubric, the model is rated 2.5/10, Common with interest I. The available evidence does not support a scarcity-based rating or a sold-market value range.

Market value

Insufficient recorded sales data to estimate a reliable value.

0 sold observations recorded; 2 are needed, with the basis and date of the range, before a value is shown. Asking prices are shown as asking prices only.

Two current asking sources list the 3670 at $17.99, but neither is a completed sale. The checked evidence therefore does not support a sold-market reference range V.

Where to find

Current evidence includes an eBay listing and a specialist salmon-fly dealer listing V.

Label and source analysis

Box Markings

A purple handwritten “12” appears on the V1 label near the printed “No.” line P. The checked evidence does not establish who wrote it, when it was added, or whether it denotes hook size, inventory, or another notation.

Modern equivalents and related hooks

Modern equivalents
HookMatchNotes
Mustad R73-9671ModerateModern Limerick bend wet fly hook but with down-turned eye rather than loop construction
Daiichi 2141GoodLimerick bend with black finish captures the traditional aesthetic though typically sold for salmon applications

Best matchRelated by Attribute

Computed automatically from catalog data — updated as new hooks are added.

SilhouetteHook ModelMatchAnalysisCompare
3671 No. 2 — Mustad 3671 Limerick silhouette3671 No. 2 — Mustad 3671 Limerick76%Matches: Bend, Eye, Eye Orient., Point, Offset +2 moreDiffers: Shank: Standard vs 1X Long; Wire: Standard vs Fine (1X Fine); Finish: Black Japanned vs Bronzed +2 moreCompare
3667 No. 9 — Mustad 3667 Limerick Hollow Point silhouette3667 No. 9 — Mustad 3667 Limerick Hollow Point71%Matches: Bend, Shank, Eye, Point, Offset +2 moreDiffers: Wire: Standard vs Heavy (1X Heavy); Eye Orient.: Turned Up vs Turned Down; Finish: Black Japanned vs Bronzed +3 moreCompare
3100 No. 5/0 — Mustad-Limerick Hooks silhouette3100 No. 5/0 — Mustad-Limerick Hooks71%Matches: Bend, Wire, Finish, Offset, Shank Feat. +1 moreDiffers: Shank: Standard vs 1X Long; Eye: Tapered Eye vs Ball Eye; Eye Orient.: Turned Up vs Straight / Inline +2 moreCompare
4707 No. 4/0 — 4707 silhouette4707 No. 4/0 — 470770%Matches: Bend, Wire, Point, Offset, Shank Feat. +1 moreDiffers: Shank: Standard vs 1X Long; Eye: Tapered Eye vs Ball Eye; Eye Orient.: Turned Up vs Straight / Inline +4 moreCompare
100 No. (unspecified) — Limerick Ringed70%Matches: Bend, Shank, Point, Offset, Shank Feat. +1 moreDiffers: Wire: Standard vs Heavy (1X Heavy); Eye: Tapered Eye vs Ball Eye; Eye Orient.: Turned Up vs Straight / Inline +3 moreCompare

ExploratoryRelated by Shape (SVG)

Ranked purely by silhouette geometry — attribute labels are ignored.

SilhouetteHook ModelMatchCompare
5795 No. 12 — Mustad 5795 silhouette5795 No. 12 — Mustad 579575%Compare
3911 No. 4 — Mustad 3911 silhouette3911 No. 4 — Mustad 391172%Compare
3718 No. 4 — Herter's No. 3718 Salmon Fly Hook silhouette3718 No. 4 — Herter's No. 3718 Salmon Fly Hook72%Compare
CS10/2 No. 4 — Bartleet Supreme silhouetteCS10/2 No. 4 — Bartleet Supreme66%Compare
94842 No. 10–24 — Viking silhouette94842 No. 10–24 — Viking66%Compare

Sources, open questions, and record notes

Sources & Documentation

This specimen and its packaging — photographed, 8 images
Supports: quantity per packageconstructioneyebendwireshankpointfinishgapbarbcondition notesmeasurement notescumulative records notemeasurements availablemeasurement methodsize measuredoverall lengthshank lengthgap widthbend depthwire diameter measureddating rangepackagingmanufacturer period contextfun fact titlefun factmeta descriptionprimary search termssummarytechnical notesseries historydesign lineageprimary applicationidentification

Open questions

  1. What are the first and last documented Mustad catalog appearances of Quality 3670?The checked evidence establishes only that the photographed Oslo-address packaging is from 1925 or later; no primary catalog appearance was located.Can you help? Please send a dated Mustad catalog or price-list page that shows Quality 3670, including the publication date and page number.

Entry last updated July 18, 2026. Entries are updated as new specimens, measurements, or documents come to light.