FOSCMB4 Dome Type Mechanical Sealing Fiber Optic Splice Closure

Deploying the FOSCMB4 dome closure across our regional FTTx distribution network solved critical maintenance and access challenges. Unlike traditional heat-shrink closures, this model utilizes a mechanical sealing structure with thermoplastic rubber grommets, allowing field technicians to open and re-seal the unit quickly without needing torches or heat guns. The 4 entry/exit ports accommodate cable diameters up to 16 mm. Constructed from high-strength Polycarbonate (PC) material rated for severe temperatures between -40°C and +65°C, the housing resists moisture and physical stress across aerial, manhole, and direct buried installations. Internally, the 4 splice trays cleanly organize up to 48 bunchy fibers or 72 ribbon fibers.

At a reference price starting at just $27 USD, FirstFiber's FOSCMB4 dome closure offers exceptional commercial value for B2B network builds. Featuring a compact profile measuring 295 (H) × 190 (D) mm and a light net weight of 1.8 to 1.91 kg, it fits easily into cramped manholes, underground pipelines, and outdoor wall-mount locations. The closure arrives as a turnkey package equipped with protective splice sleeves, nylon ties, grounding wires, port sealing rings, mounting hanging hoops, and a dedicated M10 wrench. We also opted to include the optional pressure testing valve to verify airtight sealing integrity before completing underground burial.

We standardized on the FOSCMB4 for small distribution spur points requiring clean buffer tube routing and reliable mechanical sealing. Each of the maximum 4 splice trays supports 6 single-layer or 12 dual-layer bunchy fiber splices, while a dedicated fiber holding tray safely stores un-spliced loose tube fibers. The included sealing tape and insulation tape allow field crews to quickly adapt smaller drop cables to fit the 16 mm ports. Its durable PC body and mechanical plastic hoop clamp keep the main enclosure tightly secured. It is an economical, highly re-enterable splice closure for enterprise telecom infrastructure.