MATERIAL: It is made of high quality rubber. The hook is made of premium plastic. It is strong, weatherproof, durable and corrosion resistant. Extenders with hook function: The multi-functional rubber bungee cords keep the tent stable. 25 cm elastic band with hook extensions to 50 cm. And the tarp tensioner has a plastic hook that keeps it securely in place. Rubber bungee cord with hook used: Our extensions with hooks are suitable for tarps, camping, boat shoes, tents, gardens, ramps, caravans and commercial applications. Bunggy cord with hook holder: The bungee cord easily threads through the animals and the holder, then locks onto the hooks. You can also wrap some small bungee cords to add length. Note: The data are all measured manually, please allow an error of 1 3cm Due to differences in light and display, there may be some color differences, please refer to the actual item received.