These Mil-Standard cases were designed to meet the most demanding military specifications, they are roto-molded for strength and durability, airtight and water proof with solid stainless steel latches and hinges that will withstand the most demanding shipping conditions. The 3R Mil-Std. Cases are molded of (LLDPE) polyethylene impact resistant / UV stabilized material and meet or exceed MIL-STD 810 and MIL-C-4150J specifications The shipping cases are all available with an empty interior while some models are available with: cubed foam, layered foam, padded dividers, and a pull handle with wheels. Most models without a built-in pull handle or tow handle accommodate a field installable caster kit which is sold separately. (See the accessories tab below for the 3SKB-CAST1 caster kit.) Select models are available with TSA recognized and accepted locking latches in place of stainless steel padlockable latches.