4" Square, Extension Ring, Welded, Metallic. Depth: 1-1/2". Side Knockouts: (8) 1/2" & (4) 3/4". Cubic Inches: 21.0". Combo Extension-Thru-Ring. Top has (2) 8-32 Screws & Bottom has Cutout for Switch or Handy Box.
- Knockout Diameter: 1/2 in
- Gangs: 2
- Knockout Diameter: 3/4 in
- Material: Steel
- Depth: 1 1/2 in
- Cubic Inches: 21 in³