Thomas & Betts 5303 Sealing Ring Brand: Thomas & Betts. Part Number: 5303. T&B Sealing Ring, 3/4 in, For Use With: Rigid/IMC Conduits, Santoprene TPE/Steel, Electro-Zinc Plated, 15/16 in ID x 1-1/2 in OD. Additional Description: TB -5303 RING, SEALING 3/4 RUBBER W/STL. Catalog Description: 3/4 Inch Sealing Ring, Santoprene Thermoplastic Rubber with Stainless Steel Retainer for Use with Rigid/IMC Conduit..