outer diameter is 5.06 inch with black o sealing ring 4.85inch, it is compatible with 12 inch (pump flow: 2.100 gph) sand filter pump of SF80110-1, but not for 14 and 16-inch (pump flow: 2, 800 3, 000 gph) sand filter pumps (please check your machine model before placing an order) 1 set of SF80110-1 Leaf Trap cover lid (1 swimming pool leaf trap cover, 1 valve and 2 sine joints) and 1 set of sand filter pump seal gasket parts (contains of 11 different o-ring replacement parts: 1 x vent valve; Includes 1 x Air Release Valve / Sediment Release Valve (10460), 4 x L-Shape O-Ring (11228), 1 x L-Shape O-Ring (11412), 1 x Tank O-Ring (11379), 1 x Drain Valve O-Ring (11385), 1 x O-Ring (11457), 1 x Air Release Valve O-Ring (10264), 2 x Leaf Trap O-Ring (11824 and 11232) both the leaf trap cove and the sand filter pump seal gasket parts are made of quality materials, this cover is designed to withstand the harsh filtering conditions of swimming pools; It can resist ultraviolet rays, chemicals and bad weather and provide lasting performance pool pump filter lid with an o-ring for a tight and secure seal, ensures a good fit and seamless integration with sand filter pumps; It can effectively keep leaves and debris out of your pool, maintaining a clean and clear swimming environment quick and simple, take off the old cover and replace it with this improved version, It is equipped with an annular gasket for sealing and safety sealing to prevent leakage or failure Color: As Shown Material: plastic Package Contents: 1 set * pump cover