Features: Manufactured from drop-forged Chrome Vanadium steel (smaller sizes) and Chrome Molybdenum Steel (larger sizes) Phosphate finish for increased corrosion protection Supplied in a moulded case for easy storage Specification: 3/8" (F) x 1/4" (M) = CRV 1/4" (F) x 3/8" (M) = CRV 3/8" (F) x 1/2" (M) = CRV 1/2" (F) x 3/8" (M) = CRV 1/2" (F) x 3/4" (M) = CR MO 3/4" (F) x 1/2" (M) = CR MO 3/4" (F) x 1" (M) = CR MO 1" (F) x 3/4" (M) = CR MO