Square D equipment with RB suffix, designated Rainproof (NEMA 3R rainproof construction), utilizes bolt-on hubs listed. RB devices will accept 3/4 In. through 2-1/2 In. bolt-on hubs without the use of reducers. Off-center conduit thread openings and elongated mounting holes provide quick and easy adjustment to eliminate costly conduit offsets and bends. For use in Square D load centers, CSED devices and safety switches. Type B. UL (Underwriter's Laboratories) and CSA (Canadian Standards Association) safety listed.