Thomas & Betts 422 Insuliner Insulating Sleeve Brand: Thomas & Betts. Part Number: 422. T&B Insuliner Insulating Sleeve, 1/2 in, For Use With: EMT/Rigid/IMC/Flexible Metallic Conduits, Nylon, 5/8 in L. Additional Description: TB -422 1/2 INCH NYLON INSULINER SLEEVE. Catalog Description: 1/2 Inch Insuliner Sleeve, Nylon for Use with Rigid/IMC/EMT Conduit..