Thomas & Betts 677 Erickson Conduit Coupling Brand: Thomas & Betts. Part Number: 677. T&B Erickson Conduit Coupling, Threaded, 1 in, For Use With: Rigid/IMC Conduits, Malleable Iron, 1-29/32 in OD x 1-5/8 in L. Additional Description: TB -677 ERICKSON COUPLING 1 INCH. Catalog Description: 1 Inch Erickson Coupling, Malleable Iron with Steel and Malleable Iron Ring for Use with Rigid/IMC Conduit..