W
chromium-Manganium-Molybdenum-Steel ( JIS SCM4 )
Alloy steels applied to Inlet Valves.

H
Silicon-Chromium ( Silchrom 1 ) ( JIS SUH 11 ) Apply to Inlet Valve only

A
Silicon-Chromium-Molybdenum-Steel ( JIS SUH3 ) Apply to lnlet Valves ( may apply to Exhaust Valves of light engines )

B
High Chromium-Mangane Austenitic Steel ( JIS SUH35 ) ( Anti Magnetic Steel 21-4N ) Apply to Exhaust Valves of heavy duty engines.

80A
Nimonic 80A ( NiCr20TiAl )