Carmex Tiny Tool Holder - Round Shank Holder For Swiss Machines to hold Carbide Small Boring Tool - 22mm Shank x 4mm BoreExternal turning holders for bars from the Tiny Tools family, designed for back operations on Swiss type CNC lathes with a sliding head. This holder is optimized to grip small carbide borers and is tailored for 22 mm shank tools with a 4 mm bore. Shank x Bore: Round shank 22 mm with a 4 mm bore to fit compatible carbide small boring tools. Intended Use: External turning holder designed for back operations on Swiss type CNC lathes with a sliding head.