Our Tactical Black DoorJamm is made of Neoprene rubber. This Jamm can stretch to over 2.5 times it size. This product is extremely versatile, reusable, easy to carry, and chemical resistant. The Black Jamm will withstand temperatures as hot as 220 Degrees Fahrenheit and as cold as -70 Degrees Fahrenheit. This product weighs 1 ounce and can be stored nearly anywhere on your person or kit. The Black Jamm is well liked in the tactical community due to it's ability to easily assimilate in tactical kits, the little space it takes to store and it's weight/flexibility allows operators to carry multiple Jamms, unlike other competing products.