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″ taps and the second adjustable socket fits 1/4″ through 1/2″ taps. This Irwin inovation allows the easy use and changing of various sizes of taps.