"Velco" type hook material.   This is the HOOK only side of the hook and loop system. 

3M™ Fastener Hook Flame Resistant SJ3519FR, Black, 25 mm x 45.7 m, 3.6 mm.

This item is for three rolls of 25 mm x 45.7 m, 3.6 mm hook tape.

From 3M Website:

3M™ Flame Resistant Hook Fastener SJ3519FR is one part of our two-part fastener solution designed to provide great durability for thousands of closures. This nylon, woven loop reclosable fastener features a rubber based adhesive and is flame resistant meeting F.A.R. 25.853 paragraph (a)(1)(i) 60 second vertical burn test. It mates with SJ3518FR.

A clean and simple closure solution 3M™ Flame Resistant Hook Fastener SJ3519FR offers an advanced closure alternative to zippers, screws, snaps, hooks, bolts and more. It is coated with a unique flame resistant synthetic rubber based adhesive. Our fasteners can be attached to a variety of substrates and function over a range of temperatures and humidity conditions. They provide flame resistance when tested per FAR 25.853 and other common flammability tests, and are designed to mate with 3M™ Flame Resistant Loop Fastener SJ3518FR. Recommended for securing fabric to upholstery cushions, airplane seating, carpet panel attachments, specialty vehicle and transportation applications, uniforms, gloves and clothing, signage and displays, general industrial applications, and flame resistant adhesion applications. The backing of 3M™ Flame Resistant Hook Fastener SJ3519FR is coated with a firm, pressure sensitive, synthetic rubber adhesive. The adhesive bonds well to bare and painted metal, paint, glass, sealed wood, paper, cardboard and many plastics, including low surface energy substrates such as polyethylene and polypropylene. This unique adhesive is flame resistant, enabling these hook fasteners to meet the requirements of FAR 25.853 paragraph (a)(1)(ii), a 12 second vertical burn test, when tested alone. The use of pressure sensitive adhesives eliminates or reduces the need for sewing, solvent activation, dielectric or ultrasonic bonding or bulk adhesive bonding. Eliminating these additional application procedures creates simplicity, improved safety and lower installation costs. Pressure sensitive adhesive products can be applied manually or automatically using a variety of equipment choices. 3M™ Hook and Loop design 3M™ Hook and Loop Fasteners offer great design flexibility, fast product assembly, smooth and clean exterior surfaces and excellent product performance in many applications. The woven hook is covered with about 47 tiny, stiff hooks / cm². The woven loops are covered with thousands of soft, pliable loops, providing thousands of openings and closings (cycles). The hook and loop are preshrunk to ensure maximum dimensional stability and flatness. To disengage the attachment of the hook and loop, simply pull the strips apart by hand.
Specifications

Details

Adhesive Type

Synthetic Rubber

Backing (Carrier) Material

Nylon

Brands

3M™

Closure Life

5,000

Engaged Thickness (Imperial)

0.15 in

Engaged Thickness (Metric)

3.8 mm

Industries

General Industry, Electronics, Furniture, Military and Government, Transportation, Construction, Medical, Specialty Vehicle

Maximum Operating Temperature (Celsius)

49 ℃

Maximum Operating Temperature (Fahrenheit)

120 ℉

Overall Length (Imperial)

50 yd

Overall Length (Metric)

45.72 m

Overall Width (Imperial)

1 in

Overall Width (Metric)

25.4 mm

Primary Liner Thickness (Imperial)

3 mil

Primary Liner Thickness (Metric)

0.08 mm

Product Colour

Black

Product Form

Roll

Product Type

Hook

Total Tape Thickness without Liner (Imperial)

94.488 mil

Total Tape Thickness without Liner (metric)

3.6 mm

Units per Case

2.0