Orbit 4SB-MKO-EXT 4" Square Extension Ring, Welded MKO, Galvanized Steel

Orbit 4SB-MKO-EXT 4" Square Extension Ring, Welded MKO, Galvanized Steel

The Orbit 4SB-MKO-EXT is a 1-1/2" deep, 4" square (4S) extension ring built from 16 gauge galvanized sheet steel with a welded construction and modular knockout (MKO) sides for versatile field wiring. Offering 21 cubic inches of usable box volume, this extension ring is designed to add depth and wiring capacity to existing 4" square electrical boxes, giving electricians the extra room needed for larger conductor counts, additional devices, or bulkier splices without replacing the entire box assembly. Made in the USA-standard 16 gauge steel gauge, the ring is engineered for durability in commercial and residential rough-in applications where corrosion resistance and long-term structural integrity are required.

Key Features

• Trade Size: 4" square (4S) footprint with a 1-1/2" extension depth, matching standard 4S box dimensions for a clean, flush fit.
• Durable Construction: Fabricated from 16 gauge galvanized sheet steel for corrosion resistance and long service life in rough-in electrical work.
• Welded Assembly: Fully welded seams provide a rigid, one-piece extension ring that resists flexing and separation during installation.
• MKO Knockouts: Modular knockout (MKO) sides allow installers to open only the conduit entry points needed, reducing unnecessary openings and keeping the enclosure protected.
• Added Wiring Capacity: Delivers 21 cubic inches of additional box volume, helping installations meet fill requirements when adding devices or conductors to an existing 4" square box.
• Finish: Galvanized finish for added protection against rust and moisture in a variety of installation environments.

Technical Specifications

• Size: 4" x 4" x 1-1/2"
• Volume: 21 cubic inches
• Gauge: 16 gauge sheet steel
• Material: Galvanized steel
• Construction: Welded with MKO (modular knockout) sides

Typical Applications

• Extending Existing 4" Square Electrical Boxes
• Commercial and Residential Rough-In Wiring
• Adding Box Fill Capacity for Additional Devices or Conductors
• Conduit and Raceway System Terminations
• New Construction and Remodel Electrical Installations

Why Orbit?

Orbit's 4SB-MKO-EXT extension ring is built from 16 gauge galvanized steel with fully welded seams, giving electrical contractors a rugged, code-friendly way to add depth and volume to standard 4" square boxes. The modular knockout design keeps installation flexible while maintaining the structural integrity electricians rely on for demanding commercial and residential projects.