MATERIAL: It is made of high-quality rubber. The hook is made of premium plastic. It is strong, weather-resistant, durable, and corrosion-resistant. Extenders with Hook Function: The multifunctional rubber bungee cords keep the tent stable. 25 cm elastic band with hook extensions to 50 cm. And the tarp bungee cord 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 bungee cord and the holder, then locks onto the hooks. You can also wrap some small rubber bands to add length. Note: The data are all measured manually, please allow an error of 1-3 cm. Due to differences in light and display, there may be some color differences, please refer to the actual item received.