Features and Benefits Jaws adjust to tightly secure taps from #6 to 1/2" taps 3/8" square drive compatible with common ratchets Small profile for use in tight workspaces Knurled ring twist to adjust for quick fit 2 piece set for greater versatilityBoth adjustable tap sockets are 3/8" drive, one fits #6 through 1/4"....(more info)