Hubbell 53151K Extension ring for 4 In. Square Box, 1-1/2 in. Deep, 21 Cu. In., with Concentric, 1/2 & 3/4 in., and 1/2 in. KO (50-Pack)

Hubbell 55171K Extension ring for 4 In. Octagon Box, 2-1/8 in. Deep, 21 Cu. In., with Concentric, 1/2 & 3/4 in. KO (50-Pack)

Steel City 531711234 Square Extension Ring, 30.3 Cubic Inches, 4 Inch x 2-1/8 Inch, Steel

Arlington Industries BE1 Box Extender, 1-Gang, 1-1/2 Inch Extension, 2 Hour Fire Rating, White

Thomas & Betts BCOBEX 4IN ROUND BOX EXTENSION 1/2IN DEEP

Arlington Industries BES1 Non-Metallic Box Extender 1-Gang 5/8 Inch Extension, 3.336 Inch Width, White

Arlington Industries BE2 Box Extender Plastic 2-Gang 1-1/2 Inch Fire Rated White

Hubbell 53171K Extension ring for 4 In. Square Box, 2-1/8 in. Deep, 30 Cu. In., with Concentric, 1/2 & 3/4 in., and 1/2 in. KO (40-Pack)

Hubbell 55151KBAR Extension ring for 4 In. Octagon Box, 1-1/2 in. Deep, 15 Cu. In., with Concentric, 1/2 & 3/4 in. KO (50-Pack)

Steel City 82C-2G-1 Extension Rings, 5 Inch x 5 Inch x 1 Inch Raised, 12.8 Cubic Inches, Pre-Galvanized Steel

Hubbell 1110RBAR Extension ring for Utility Box, 1-7/8 in. Deep, 16.5 Cu. In., 1/2 in. KO (10-Pack)

Steel City 82-52E-1/2 Square Extension Rings, 5 Inch x 5 Inch, 7.2 Cubic Inches, Steel

Steel City 82C-2G-1-1/2 Extension Rings, 5 Inch x 5 Inch, 20 Cubic Inches, Pre-Galvanized Steel