Drop forged, heat treated steel. Chrome plated for added durability and to resist rust and corrosion. Thin, but extra strong design, to reach confined working areas where traditional wrenches cannot reach. Includes roll-up storage pouch. Sizes- 8mm x 9mm, 10mm x 11mm, 12mm x 13mm, 14mm x 15mm, 16mm x 17mm, 18mm x 19mm, 20mm x 21mm, 24mm x 27mm, 30mm x 32mm.