This is Diversi-Tech High Security, Stainless Steel Tube Key style Lock, part number DT40124. This lock features a 3/8 inch diameter shackle and creates a 7/8 inch opening when unlocked. The exterior shell is made of stainless steel and the shackle is made of chrome plated hardened steel. The internals are made of brass. There are 2 tube keys included with the lock and the lock is covered by a limited lifetime warranty. The lock can be used on trailers, toolboxes, or anything that will accommodate a 3/8 inch diameter shackle. And that does it for the Diversi-Tech High Security, Stainless Steel Tube Key Style Lock, part number DT40124.