This is a 36L rear box. It comes with a key for security. It also has a backrest, making it less tiring on touring trips. It's large enough to store a helmet without any problems, and it's convenient for shopping or commuting. A dedicated base for easy tool-free installation is included. It's waterproof, so you can use it without worry on rainy days. Brand new and unused. Shipping will be within 2-3 days. Immediate purchase is welcome.