A spring steel ringlike item designed to be placed between a piston ring and the piston to maintain the correct piston ring pressure against the cylinder wall.
NSN
NSN 6620-01-549-3559
NSN 5975-01-415-0918
NSN 5990-01-322-9781
NSN 6110-01-436-9740
NSN 5945-01-239-8190
NSN 6645-01-261-0056
NSN 6150-00-113-8619
NSN 5935-01-519-6531
NSN 6620-01-116-3983
NSN 6685-01-268-1465
NSN 5999-00-039-6898