3M™ Dual Lock™ Reclosable Fastener SJ3440, Black, 1 in x 50 yd, Type 250, 2 Roll/Case

3M™ Dual Lock™ Reclosable Fastener SJ3440 is the easy and clear alternative to traditional fastening methods, such as screws, nuts or bolts. It is designed to deliver a durable, reclosable fastening solution, which can be opened and closed multiple times. This black fastener is most commonly attached by applying hot melt, epoxy or liquid adhesive.
Special Price $355.35 Regular Price $418.06
UPC 00021200658082
3M ID 7000001979
Packaging Case
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Unlock Simplicity

Durable and secure, 3M™ Dual Lock™ Reclosable Fastener SJ3440 has exceptional strength through its interlocking mushroom-shaped heads (250 stem density per square inch). With 3M™ Dual Lock™ Reclosable Fastener SJ3440, there is no need for any drilling or screwing. This fastener is most commonly attached by applying hot melt, epoxy or liquid adhesive.

Recommended Applications:

Alternative to pressure sensitive adhesives

Design Flexibility

3M™ Dual Lock™ Reclosable Fastener SJ3440 consists of interlocking mushroom-shaped heads that easily slide over each other, allowing for positioning of parts before being snapped together. This fastening process creates a durable attachment and provides fast product assembly with great design flexibility. Reclosable fasteners can also engage with different stem densities for varying levels of strength and system performance.

3M™ Dual Lock™ Reclosable Fasteners sound an audible snap when secure, which verifies closure of the attachment. To disengage, simply peel the pieces apart by hand. These fasteners maintain their strength throughout multiple attachments and detachments. A lightweight alternative to metal fasteners, this product remains hidden beneath surfaces and does not interfere with the integrity of your material—providing aesthetic improvements and design flexibility.

Hundreds of Reattachments in a Snap

When two pieces of 3M™ Dual Lock™ Reclosable Fasteners mate, the stems flex and the mushroom heads slide past each other. After passing the opposing mating piece, the stems snap back into their original position and the opposing mushroom heads interlock. These fasteners can provide high tensile strength but can be opened by simply cleaving or peeling open the closure. This product is well suited for many indoor applications where a good performance, high strength, reclosable fastening system is required.

Delivers Long-Lasting Performance

Not all design requirements are easily satisfied, but you can simplify your attachments. When you need a strong, reliable, yet removable closure, 3M™ Dual Lock™ Reclosable Fasteners are the easy alternative to traditional fastening methods such as screws, nuts or bolts.


  • Black, interlocking mushroom-shaped heads (250 stem density per square inch) provide strong, reliable and durable fastening that can be opened and closed multiple times
  • Mates with Type 170, Type 250 or Type 400 stem densities to provide different strength combinations
  • Non-adhesive back for attachment with hot melt, epoxy or liquid adhesives
  • Strong fastener secures with an audible snap, verifying closure
  • An alternative to screws and bolts, this hidden fastener provides a snug fit and smooth aesthetic appearance
  • Features good temperature resistance of 220°F (104°C), though temperature resistance may change based on adhesive used
  • Suited for indoor or outdoor use
More Information
3M ID 7000001979
Part number SJ3440
Keywords 3M, Dual Lock, Reclosable Fastener, SJ3440, adhesive fastening solution, interlocking mushroom-shaped heads, durable fastener, reclosable fastening, alternative to screws, alternative to bolts, epoxy adhesive, hot melt adhesive, liquid adhesive, strong fastening, indoor use, outdoor use, high tensile strength, automotive applications, commercial solutions, electronics bonding, manufacturing fastener, transportation fastener, aerospace fastener, building maintenance, DIY fastening, marine fastener, woodworking fastener, hidden fastener, design flexibility, audible snap fastener, repositionable fastener, reliable closure, high strength reclosable fastener, non-adhesive back.
Global Product Hierarchy Tapes > Reclosable Fasteners > Mushroom Hook Fasteners
Application Attaching Graphics, Kiosk Assembly, Panel Attachment Systems, Sensor Attachment
Backing (Carrier) Material Polyolefin
Color Family Black
Product Color Black
Product Number SJ3440
Product Type simple
Quantity 0
Trademark 1 3M™
Trademark 2 Dual Lock™
Country of Origin United States
Sales Unit RO
SAP Shelf Life In Days 730
Base - Billing Unit ROL
Base - Customary Height Dimension 1
Base - Customary Length Dimension 20.37480315
Base - Customary Width Dimension 20.37401575
Base - Metric Gross Weight 1.123 KG
Base - Metric Height Dimension 2.54 CM
Base - Metric Length Dimension 51.752 CM
Base - Metric Width Dimension 51.75 CM
Base - Item Quantity 1
Base - Unit ROL
Unit of Use - Billing Unit ROL
Unit of Use - Customary Cubic Dimension 415.11658220166834 ci
Unit of Use - Customary Gross Weight 2.475791204336175 lbs
Unit of Use - Customary Net Weight 0.9920801798319491 lbs
Unit of Use - Customary Height Dimension 1.0 in
Unit of Use - Customary Length Dimension 20.3748031496063 in
Unit of Use - Customary Width Dimension 20.374015748031496 in
Unit of Use - Metric Cubic Dimension 6802.542 CCM
Unit of Use - Metric Net Weight 0.45 KG
Unit of Use - Metric Height Dimension 2.54 CM
Unit of Use - Metric Length Dimension 51.752 CM
Unit of Use - Metric Width Dimension 51.75 CM
Unit of Use - Item Quantity 1
Unit of Use - Total Unit Quantity 1
Unit of Use - Previous Packaging Level Quantity 1
Unit of Use - Item Unit RLS
Unit of Use - Unit ROL
Shipper - Billing Unit ROL
Shipper - Customary Cubic Dimension 1230.8489183907502 ci
Shipper - Customary Gross Weight 5.949835531845476 lbs
Shipper - Customary Net Weight 1.984380821926083 lbs
Shipper - Customary Height Dimension 2.795275590551181 in
Shipper - Customary Length Dimension 20.984251968503937 in
Shipper - Customary Width Dimension 20.984251968503937 in
Shipper - Metric Cubic Dimension 20.17 CDM
Shipper - Metric Weight 2698.8 G
Shipper - Metric Net Weight 900.1 G
Shipper - Metric Height Dimension 0.071 M
Shipper - Metric Length Dimension 0.533 M
Shipper - Metric Width Dimension 0.533 M
Shipper - Item Quantity 2
Shipper - Total Unit Quantity 2
Shipper - Previous Packaging Level Quantity 2
Shipper - Previous Packaging Level Unit RLS
Shipper - Item Unit RLS
Shipper - Unit CS
Pallet - Billing Unit ROL
Pallet - Customary Cubic Dimension 81344.65087827813 ci
Pallet - Customary Gross Weight 339.51188376471146 lbs
Pallet - Customary Net Weight 103.18736181563195 lbs
Pallet - Customary Height Dimension 40.94488188976378 in
Pallet - Customary Length Dimension 47.63779527559055 in
Pallet - Customary Width Dimension 41.732283464566926 in
Pallet - Metric Cubic Dimension 1.333 M3
Pallet - Metric Net Weight 46.805 KG
Pallet - Metric Height Dimension 1.04 M
Pallet - Metric Length Dimension 1.21 M
Pallet - Metric Width Dimension 1.06 M
Pallet - Item Quantity 104
Pallet - Total Unit Quantity 104
Pallet - Previous Packaging Level Quantity 52
Pallet - Previous Packaging Level Unit BOX
Pallet - Item Unit RLS
Pallet - Unit PAL
Pallet - Pallet Layer Quantity 13
Pallet - Shipping Container Per Layer Quantity 4
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