I have worn this a few times but have never had to use it. It is designed to wear while riding. The best has an air cartridge in it. There is a strap that attaches to the saddle. In the event of a fall it inflates protecting the upper body. This is great for young riders and old ones like me. It is a bit dusty in the pics but will arrive cleaned off. If you have any questions, please let me know. Pics are accurate description.