3M SJ3550 Dual Lock Type 250

This black fastener has mushroom-shaped stems on a polypropylene carrier which is coated with a white, general-purpose acrylic pressure-sensitive adhesive.
Type 250 stem density fasteners can mate to type 170, 250 or 400 fasteners (the higher the combined number the greater the closure strength).
Mushroom-shaped stems on one side of the fastener interlock with identically shaped stems on the other side for 5X greater closure strength than hook and loop.
Pins: 250 per square inch. Engaged Thickness: 230 mils. Thickness: 140 mils (carrier, adhesive) 4 mils (liner).
Adhesive: acrylic (300 LSE). Carrier/Backing: polypropylene.
Service/Operating Temperature up to 200F Release Liner clear polyolefin film.

3M SJ3550 Dual Lock 250 Recolorable Fastener is a general-purpose black recolorable fastener with 250 stems per square inch.
An engaged thickness of 0.23 inches and a closure life of 1,000.
Type 250 stem density fasteners can mate to type 170, 250 or 400 fasteners (the higher the combined number the greater the closure strength).
Mushroom-shaped stems on one side of the fastener interlock with identically shaped stems on the other side for 5X greater closure strength than hook and loop.
Used to attach doors, access panels, signs, cushions, wall headliners, display components, city bus light fixtures, ceiling attachment, privacy curtain rails, sunroof trims, and wall panels.
Also for POP (point of purchase), trade show exhibition and electronics, and for attaching E-Zaps tags to car windshields