Product Type Venting For Gas Heaters, Compatible with Product Type Wall Furnaces, Compatible Grainger Part Number 36FK27, 36FK28, 36FK30, 36FK31, Compatible Mfr. Model Number 2203821, 2209822, 3003821, 3003822, Opening Height 9 in, Opening Width 9 in, Opening Depth 9 in, Mounting Type Top, Vent Direction Horizontal, Vent Length 15 in, Vent Diameter 9 in, Vent Size 9 in, Vent Type Sidewall Venting, Flapper Length 15 in, Material Steel, Outer Diameter 9 in, Overall Length 15 in