This Master Lock 1480DAT Stainless Steel Receiver Lock for 5/8” Receiver Hole has hardened receiver pins for increased sheer strength, and a precision 4-pin tumbler mechanism that resists picking. There is a K1 key blank for all receiver locks and this lock retains key for increased safety. Whether you need a master keyed padlock or an integrated padlock and door lock system, Master Lock offers the breadth of keying capabilities to find the optimal match for your specifications: keyed alike; master keyed; padlock cylinders; interchangeable core cylinders; door key compatible cylinders and patent pending key control key ways. Also, Master Lock designed the Pro Series and Rekeyable Padlocks for easy cylinder replacement service.