Source Square Extension Ring box 4X4 Electrical Metal Junction Box on m.alibaba.com
ReceptXtenders 1-Gang 1/2 in. Electrical Receptacle Box Extension Ring (5-Pack) HD50004 - The Home Depot
Garvin 57111 4 Inch Round Pan Box Extension Ring, 1/2 Inch D
Steel City 53151 1/2 3/4 Pre-Galvanized Steel Square Box Extension Ring with 1/2-Inch and 3/4-Inch Knockouts - Ring Terminals - Amazon.com
4" Square Extension Ring, 2-1/8" Deep - Drawn, W/Conduit KO's | Garvin Industries
4" Square Plenum Extension Ring, 1-1/2" Deep - Drawn, W/Conduit KO's | Garvin Industries
Steel City 4 in. 21 cu. in. Square Box Extension Ring 531511234-20R - The Home Depot
4" Octagon Extension Ring, 2-1/8" Deep - Drawn W/Conduit KO's And Fixture Ears 3-1/2" O.C. | Garvin Industries
Appleton 4SES :: 4" Square Extension Ring, 1-1/2" Deep, Drawn, Metallic :: PLATT ELECTRIC SUPPLY
Hubbell-Raco 187 :: 4" Square Extension Ring, 1-1/2" Deep, Drawn, Metallic :: PLATT ELECTRIC SUPPLY
Vello Manual Extension Tube Set for Nikon F-Mount EXT-NFM B&H
Sigma Engineered Solutions 1-Gang Gray Metal Weatherproof New Work Standard Box Extender Exterior Electrical Box in the Electrical Boxes department at Lowes.com
RACO 4 in. W x 1-1/2 in. D Drawn Octagon Extension Ring with Two 1/2 in. and Two 3/4 in. Knockouts, 1-Pack 130 - The Home Depot
Circular Extension Ring 20mm - Marshall-Tufflex
4 in. x 2 in. Handy Extension Ring, Drawn, 1-7/8 in. Deep, Eight 1/2 in. KO's | 665 | Raco
Extension tube - Wikipedia
Steel City 59361-1/2 Handy/Utility Outlet Box Extension Ring, Drawn Construction, 4-Inch Length by 2-1/8-Inch Width by 1-7/8-Inch Depth, Galvanized - Outlet Plates - Amazon.com
531511234UB - Steel City 531511234UB - 4" x 1-1/2" Deep Square Box Extension Ring w/ 1/2" & 3/4" Eccentric Knockouts
1/2" Octagon Box Ring Extension - Amazon.com
531711234 - Steel City 531711234 - 4" x 2-1/8" Deep Square Box Extension Ring w/ 1/2" and 3/4" Knockouts
Extension Ring – Squarehood
Steel City 1-Gang 3 1/2 in. New Work Pre-Galvanized Metal Octagon Electrical Box Extension Ring (Box/Conduit/Fitting Accessory) 2515112-25R - The Home Depot
ERA BRAND PVC-U INSULATING ELECTRICAL PIPE LOCATING FLANGES
Appleton 4SSBESPL :: 4" Square Extension Ring, 1-1/2" Deep, Welded, Metallic :: PLATT ELECTRIC SUPPLY
