Northern Tool offers the Ironton Impact Adapter 8-Piece Set for $14.99. Opt for in-store pickup to dodge the $7.49 shipping fee. That's tied with last month's mention, $15 off, and the lowest price we could find. Made of chrome vanadium steel, these adapters are designed for use with air tools and impact sockets. The set includes 1/4" x 3/8", 1/2" x 3/8", 1/2" x 3/4", 1" x 3/4", 3/8" x 1/4", 3/8" x 1/2", 3/4" x 1/2", and 3/4" x 1" adapters, all in a heavy-duty plastic case.