3M 7000001979 Dual Lock Reclosable Fastener SJ3440 Black

Product Description

The 3M 7000001979 is a plain-backed, no-adhesive Dual Lock reclosable fastener supplied in a 1-inch-wide by 50-yard roll in black. It features 250 mushroom-shaped stems per square inch and an engaged thickness of 4.0 mm (approximately 0.16 inches). When two mating strips are pressed together, the interlocking stems develop tensile strength high enough to substitute for screws, rivets, and other mechanical fasteners. This fastener is suited for trade and industrial applications where a clean, repositionable, tool-free mechanical connection is required.

The SJ3440 has seen broad use across transportation, electronics, business equipment, machinery, medical devices, and sign and display installations. Its plain-backed construction means no peel-and-stick adhesive is present, making it appropriate for applications where the substrate is bonded or primed separately, or where the fastener is sewn, riveted, or otherwise mechanically attached to a surface.

Key Features

• 250 stems per square inch for high-cycle reclosable engagement
• Plain-backed with no adhesive — substrate attachment method is user-determined
• Engaged thickness of 4.0 mm (0.16 inches) per mated pair
• 1-inch width and 50-yard length per roll for flexible cut-to-length use
• Black color for low-visibility or concealed fastening applications
• Mushroom-stem interlock delivers tensile strength capable of replacing mechanical fasteners

Compatibility

Designed as an OEM-style reclosable mechanical fastener for use in transportation, electronics, machinery, medical, and sign and display applications where mating Dual Lock strips of equivalent stem count are used on opposing surfaces.

Installation Notes

Installation is typically performed by fabricators, field technicians, or assembly personnel depending on the end application. When mounting to a surface, confirm that the substrate is clean, dry, and compatible with the chosen attachment method before securing the plain-backed fastener. Cut strips to length with sharp shears or a utility knife. Align opposing strips carefully before engaging, as the interlocking stems resist repositioning once fully pressed together.

Technical Specifications

• Stem Density: 250 stems per square inch
• Engaged Thickness: 4.0 mm (0.16 inches)
• Width: 1 inch
• Length: 50 yards per roll
• Color: Black
• Backing: Plain, no adhesive
• Unit of Measure: Roll
• Weight: 2.98 pounds
• UPC: 00021200658082

Standard Information

• Brand: 3M
• Manufacturer Part Number: 7000001979