The SB Tools 002306 Taper-Lock Adapter Sleeve 3/8" is part of SB Tools' Taper-Lock Handle System. It works in conjunction with the Bolster (sold separately) to adapt 3/8" diameter round bladed non-SB brand tools to the Handle.
NOTE: European bowl gouge manufacturers may measure the size of the gouge blades differently than American manufacturers. Be sure to measure the actual OD of the blade to select the correct size. USA