Foredom Duplex Spring Hammer Handpiece Great for Flex Shafts. This is a new Foredom #15D hammer handpiece. Close bezels and heavy prongs, set stones in channels and create unique textures with this handpiece. Has a duplex spring for extra flexibility. Has a 1/32" (1 mm) stroke with adjustable impact. Comes with an anvil point and a wrench. It measures approximately 6" (152.5 mm) long.