Square D Type QOU breaker are Feed-thru and DIN rail mountable, 20A 1Pole 120V. This frame configuration (cable in-cable out) is favored by panel builders and OEM manufactures. Square D is the Cadillac of all brands and favored by the majority of electricians. Unique is the trip window indicates a tripped circuit. Common Trip, Thermal Magnetic, 1-3 Poles, 120/240 VAC At 50/60 HZ (Underwriters Lab/CSA), 48 VDC, 15-100 Ampere, Interrupting Rating 10 Kiloampere At 120/240 VAC (Underwriters Lab/CSA), 5 Kiloampere At 48 VDC, Wire Size 14 To 8 Awg Aluminum/Copper, (2) 14 To 10 Awg (Copper), Plug On Mounting, Size 2.25 Inch W X 2.91 Inch D X 3 Inch H, Approval Underwriters Lab, Used On Qo Load Center, Nqo Panel board, OEM Interior/Speed-D Switchboard Distribution Panel, QOU is a registered brand of the Square D Company, QOU Model.