Marlen Manufacturing All-flexible Basic Flat Mounting Ring 1-1/4" Opening, 3-3/4" Diameter, Green Neoprene Rubber Marlen Basic Flat All-Flexible Mounting Ring is for persons with flat abdomens, good muscle tone and protruding stomas. Specially meant for those with average or larger builds with centrally located stoma and adequate clearance on all sides. Comes in Green Neoprene rubber