This adapter adapts a 516" press to a 3/8" size. Takes about 7/8" away from the height of your press. Thumb Screws can be purchased separately
This is needed on some tooling that has 3/8 stem instead of 5/16. For example there are some attachments designed for the Little Wonder, that can be used with the Handyman with this adapter. The 65-6163 Jiffy Rivet Setter is one common example.