The Notifier SBB-B4 Cabinet Backbox is a two-tier enclosure designed for use with Notifier CAB-4 Series fire alarm control panel cabinets. The backbox forms the structural mounting enclosure for ONYX Series fire alarm system components, including control panels, chassis assemblies, power supplies, and batteries.

The cabinet backbox is constructed from 16-gauge steel and includes multiple conduit knockouts to simplify wiring entry during installation. It is engineered to support modular system configurations by accommodating various chassis and system modules used within Notifier intelligent fire alarm control panels.

The SBB-B4 backbox is designed to be paired with a compatible DR-B4 cabinet door to complete the cabinet assembly. Optional accessories such as trim rings, battery plates, and wiring channels can be added depending on system requirements. These accessories allow installers to configure the cabinet for power supplies, batteries, and multiple system modules.

The cabinet supports left- or right-hand door hinge configuration and allows the door to open up to 180°, providing easy service access for maintenance and system expansion. This enclosure is commonly used with ONYX Series panels such as the NFS2-3030 and NFS2-640 when configured with two-tier cabinet space requirements.