DAYTON 3F817 - DUAL VENT KIT,FLANGE-MOUNT, STEEL - PRODUCT TYPE VENTING FOR GAS HEATERS, COMPATIBLE WITH PRODUCT TYPE DAYTON INFRARED TUBE HEATERS, OPENING HEIGHT 4 IN, OPENING WIDTH 4 IN, OPENING DEPTH 6 IN, MOUNTING TYPE FLANGE-MOUNT, VENT DIRECTION...