Original Marine Piston Set For Cummins 6bt 5.9L 12v- STD- 3800756/3802830 64MM for 1 cylinder. 1 set ring for one piston. 2 pcs piston pin lock. For one engine of 6bt 6 cylinder you need to order 6 pcs of this item.Let us know if you need anything else other than the mentioned part. We have wide range of parts for 6bt.