GATOR GRR6L. The Gator Cases GRR-6L Roller Rack Case (Black) is a high-density military-grade lightweight polyethylene case with 6 RU of space and 18.75" rackable depth. The case has front and rear rack rails and threaded field-replaceable 7.0mm zinc-plated-steel rack rails. It has locking front and rear lids and heavy-duty twist latches. The case can be transported using the comfortable recessed side handles, a rugged pull-out handle,and roller-blade-style recessed wheels. Features: High-density military-grade lightweight polyethylene case with 6 RU of rack space and 18.75" of rack depth Front and rear rack rails Threaded field replaceable 7.0mm zinc-plated-steel rack rails Locking front and rear lids Heavy-duty twist latches Heat treated 10/32 bolts with protective washers included