Spec Sheet Preview: The Alpha Communications® BBF (flush) and BBS (surface) series back boxes are designed for a variety of applications. All models (except the BBS910) are fabricated of 18 gauge (.047" nominal) CRS (Cold Rolled Steel), bonderized with powder-coated baked enamel painted finish. The BBS910 is an aluminum welded box, sealed for water resistance. It is powder coated in a Bright Yellow enamel finish, for optimal visibility. Where applicable, construction is spot-welded, with 1/2" knockouts for wiring, where applicable. Model BBF863 has five (5) 7/8" knockouts. All models have station mou …