Material  | Steel Pre-galvanized  | 
Size  | 3/4&1" K.O.  | 
Type  | Drawn  | 
Standard  | UL 514A  | 
Depth  | 2-1/8"  | 
Thickness  | 1.0mm - 1.6mm  | 
Usage  | 4" Square (4S) Boxes Extension Rings are used to install lighting fixtures, switches, and receptacles in ceilings and walls, with both welded steel and drawn steel construction.  | 
