Keystone SLX-Series Side Door Elevators are casing elevators designed for casing and drill collar. They are load rated at 150, 250, and 350-tons and come in sizes from 3 ½” – 22 5/8”. The ears on the SLX 150, 250, and 350-ton are designed so the elevator can rotate freely in the bails when used for picking up or laying down pipe.