This sump pit is designed to be used as a collection point for Radon gas as well as house the Liberty 237 sump pump. It has a 3" vent hole in the lid for venting Radon gas and odors outdoors and a 1 1/2" water discharge. The basin is 17" deep by 18" wide and has pre-drilled weep holes in the sides for optimum water management. This sump pit must be set in the ground with 2-3" of pea stone...