Sealey Adjustable Tap Socket Set Tapping Reaming 3/8" Drive Tight Spaces 2 piece. Manufactured from carbon steel. Use for accurate tapping and reaming in tight spaces. Fits onto 3/8" Square drive ratchets. Knurled ring twists to help tighten taps securely. Fits taps with shank size up to 10mm. Maximum Square Size: 4mm, 7mm.