Our QUIETCOOL ES RM 1100CRB  FLAT ROOF mount whole house fans are designed for many different applications and are intended to provide a means for whole house cooling of dwellings that do not have an accessible attic or have limited attic space. These are ideal for Standard roofs, flat roofs, cathedral ceilings, manufactured/Mobile homes and structures that employ 'T' bar suspended ceilings. These work great for commercial buildings, office buildings, portable offices/classrooms, retail strip mall stores.The energy efficient split capacitor motor has thermal protection built in.The RM 1100CRB  fans have 3 different models:FLT---for flat to slight sloped roofs up to 2 and 12 pitches.CRB---for curb mounted applications with flat to slight sloped roofs up to 2 and 12 pitches.SLP---for sloped  roofs up to 6 and 12 pitches.Price is for the roof mount assembly only. Please call when purchasing this product so we can verify you are getting the most correct product !