This listing includes five duplex lever springs, part number RC4-3245 (also referenced as RC4-3245-000CN).These components are compatible with printer models M402, M403, M426, M427, M501, M506, and M527.They also fit units identified by the series numbers 402, 403, 426, 427, 501, 506, and 527.This spring serves as a functional replacement to restore the mechanical of the duplex lever assembly in the specified devices.