... junction box, outlet box, drywall mud box, standard 1900 box, square conduit box, 4” square box, 4” square junction box, 4” square outlet box, standard 1900 box, 1900 plenum box, standard 1900 plenum box, vapor tight box, fire alarm box.4" Square Junction Boxes:1. 4" Square Junction ... solution for old work "cut in" applications or new construction. Waterproof 4"Square Junction Box CB894