These fans are designed to boost air flow in long sections of warm air furnace duct when insufficient heat is attained at a distant register Duct fans are also effective in aiding the transfer of heat through walls to adjoining rooms when installed in short sections of duct in the wall.
FEATURES - UL approved motor - Designed for use where temperatures will not exceed 190F - Compressible foam outer ring for easy mounting in proper size duct - Stabilizing ab for mounting in rectangular duct - Complete with wirenuts, grommet, screws and instructions
Duct Booster Fans 
These fans are designed to boost air flow in long sections of warm air furnace duct when insufficient heat is attained at a distant register Duct fans are also effective in aiding the transfer of heat through walls to adjoining rooms when installed in short sections of duct in the wall.