OEM Systems RIB-62 Rough-In Kit for AP602 and PS602: * Mounting straps span 24" members * Dome/mounting flange slides along straps * Substantial friction holds ring fast * Inexpensive * Versatile * Wire inlet * Shields speaker for insulation * Metal straps span 16" centers * For all dual 6-1/2" rectangular in-wall models * Mouth opening: 8" x 11-3/4"