The 58STA/58STX 4-way multipoise gas furnaces feature Carrier's QuieTechTM noise reduction system for incredibly quiet induced draft operation. Applications are easy with 4-way multipoise design, through-the-furnace downflow venting, 13 different venting options, and a door designed for easy service access. An inner blower door is provided for tighter sealing in sensitive applications. The 58STA furnace is approved for use with either propane or natural gas. The 58STX furnace is approved for use with natural or propane gas, and for use in Low NOx Air Quality Management Districts.