Hubbell-Raco 232-OW Old Work 2-1/8-Inch Deep Square Box Kit, Welded with 206RAC, (8) 1/2-Inch & (4) TKO Eccentric Side Knockouts, 4-Inch With proper fitting can be used for conduit, nmsc, armored, metal clad, flex cable Ideal for mounting life safety notification devices in old work applications 30.3 cu. In. Capacity Acceptable for use in two hour fire rated wall The product is ul listed