4 Screw Mount With Right Side Fill.46 Cu. In. Made Of High DensityPolyethylene With Uv Additive.Includes O-Ring & Fill Cap With Screen.Replaces Merc # 88316A1.RES500L Is Used On API #?s PT500N-2,PT505N-2, PT524N-2Arco# M532 Sierra# 18-6778