All Kibblewhite Precision Machining, Inc. stainless steel valves are impregnated by a special German process with a .002" deep & .0002" surface build-up to improve wear properties and reduce friction This improves wear properties, reduces friction, and provides resistance to corrosion and wear that is superior to chrome and nickel electrolysis plating Designed using Finite Element Analysis software, and profiles are tested on our computerized flow bench Black Diamond Valves are light, strong, one piece forgings with profiles that provide excellent flow characteristics Head Diameter: 1.750" / 44.45 mm; Stem Diameter 0.3760"; Tulip 29°; Overall Length 3.820"; Remarks Standard Replaces OEM 18082-57