An in-ground pool skimmer built for vinyl and fiberglass pools, the SP10841 pulls surface debris into its 163-cubic-inch basket before it reaches your filter, with a snap-in weir that self-adjusts to water level changes of up to 4.5 inches. The seamless ABS body has no joints below the waterline, and the square cover collar allows up to 1.5 inches of vertical adjustment for a clean deck fit. It uses 1.5-inch FIP threads and includes a 3/4-inch auxiliary knockout port that can serve as an overflow or water fill line.