Perko Anchor Chocks High quality chrome plated bronze construction. Fits: Fortress: FX7 - FX16; U.S. Anchor Mfg.: 2-1/2, 4, 8, 13; Danforth: H500, H960, H1500, S160, S300, S600, S920, S1300, VSB160, VSB13000, VSB1900, T570, T1200, T1800, T2500, T3000, D375, D750, D1150, D1650