New Old Stock Piston, the part was purchased in a old dealer buyout part dated 1951.

PN 43-205 375582 STD

Used on the following Models HS, HD,  and HA:

HS-39, HA-39, HD-39, HS-10, HA-10, HD-39, MS-15, HA-15, HS-15, HS-20, HD-20, HD-25, HD-26