Lifegard AF-92 Heater Modules,Single Capacity Single Capacity for Aquariums up to 100-gallons It accepts 1-inch or 3/4-inch diameter aquarium heater; (Aquarium heater element is not included with module) Overflow pipe automatically vents air from chamber for safe operation Inlet Port 1-1/4-inch Slip/3/4-inch FPT; Outlet Port 1-inch Slip/3/4-inch FPT; Port size dimensions listed are pipe size; SLIP equal to PVC solvent socket type fittings All Lifegard Mechanical, Chemical, Heater, and UV Sterilizers include 3/4-inch threaded reducing bushings if threaded installation is desired