Lunati Steel Retainers are made from 4140 chrome moly steel, which is stronger and harder than standard 1020 steel. This increased strength to weight ratio results in a stronger yet lighter retainer. Steel retainers are available for 5/16?, 11/32" and 3/8? valve stem diameters as well as 7? and 10? locks. All steel retainers from Lunati are black oxide coated for corrosion resistance.