A duct is a pipe, tube, or channel that carries air, gas, exhaust, or liquid from one location to another. Ducts are commonly used to expel heat and fumes away from commercial ovens, stoves, condensing units, and other restaurant equipment. A retainer is a positioning mechanism, such as a device, frame, or slot that grips, holds, or guides. A retainer may also be a clip, bracket, or similar component that prevents a part within a machine from moving. Specifications: Height: 0.9 inches. Width: 6.55 inches. Length: 1.65 inches.