High-impact polymers are molded to fit a wide variety of sizes and models securely and with uncompromising protection. Includes a D-ring to make adding a strap a snap! SKB is our premier supplier of instrument and gear cases. SKB builds their products with military-spec ultrahigh molecular weight polyethylene and premium hardware. All SKB hardshell cases are unconditionally guaranteed forever. That means if you break it they will repair or replace it at no cost to you.