Thomas & Betts WA151 Steel City Reducing Washer. Steel City Reducing Washer, 1-1/2 x 1/2 in Size, For Use With: Rigid/IMC Conduits, Steel, Zinc Plated, 7/8 in ID x 2-5/8 in OD Dimensions. Additional Description: TB -WA151 1 1/2 -1/2 REDUCING WASHER,RGD/IMC,. Catalog Description: 1-1/2 Inch to 1/2 Inch, Reducing Washer, Steel-Zinc Plated, For Use with Rigid/IMC Conduit, CSA Listed.