The RM325H and RM326H are designed for use with the Rangemaster® RM60000 series. All our blowers are designed for quiet operation using the finest motors and balance wheels. Rough-in kits are included to make the installation clean and simple. 1200 CFM Blower for interior mounting 4" x 18" ducted for RM60000 Series. Transitions for 10" round duct available. Damper purchased separately (Model 421, see accessories below)