J&d manufacturing’s shaded pole blowers are designed to be used in double sided poly greenhouses. Both models have adjustable damper doors to adjust air flow as poly expands in heat or as small holes develop. Brackets allow the blowers to be mounted to a post or tube. features: totally enclosed motor with thermal overload protection adjustable air flow damper metal blower wheel – no plastic no open or exposed wires or connections sealed unit will not allow dust or moisture to get into motor rubber seal between motor and blower for smooth operation junction box with knock out for easy wiring brass set screw for ground wire rubber grommet seal for wires on corded models fits industry standard mounts 2 – 7/8in x 4in on center bolt pattern individually boxed 1 year warranty