Check the listing for details. Cooper Wheelock CW-CBB-8 Circular Backbox, Flush-Mount, 9.75x1.4". Condition: New. Listed at 9.11 USD. The Cooper Wheelock CW-CBB-8 Circular Backbox is a flush-mount enclosure engineered to house 8-inch ceiling speakers and speaker-strobe devices in fire alarm and life safety systems. Constructed from durable steel, it ensures a secure and code-compliant installation in both new-construction and retrofit ceiling tile applications. The backbox features a compact outer diameter of 9.75 inches with a depth of 1.4 inches, providing ample internal volume for wiring while maintaining a low profile that minimizes visual impact. Knockouts for ½-inch and ¾-inch conduit entries simplify installation, and it is fully compatible with Cooper Wheelock S8 series ceiling appliances to preserve UL listing and plenum-rated safety. Its circular design allows seamless integration into ceilings while providing.