PROMATE Alpha-BP Durable Anti-Theft Laptop BackpackPROMATE Alpha BP Durable Anti Theft Laptop Backpack The Alpha BP combines practical storage options with a stylish design that won't look out of place in any home or office environment. Its main features include a huge compartment that can fit up to 15. 6" laptops, polyester lined inner material, and padded shoulder straps, which offer maximum security for your belongings and comfort during use.