Steel City 551511/2-25 Octagon Box Extension Ring, 4 Inch Diameter x 1-1/2 Inch Deep, 15.8 Cubic Inches

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

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)

Hubbell H53151KBAR 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 H53171KBAR 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 H55151KBAR 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)

Hubbell H73171KBAR Extension ring for 4-11/16 In. Square Box, 2-1/8 in. Deep, 42 Cu. In., with Concentric, 1/2 & 3/4 in., and 1/2 in. KO (30-Pack)

Hubbell H1110RBAR Extension ring for Utility Box, 1-7/8 in. Deep, 16.5 Cu. In., 1/2 in. KO (10-Pack)

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

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

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

Steel City 82C-1G-1/4 Single Gang Extension Ring, 5 Inch x 5 Inch, Steel, 1.5 Cubic Inch