Marketing InformationRoof mounted belt drive downblast ventilators are designed to exhaust air out of commercial and industrial buildings. All models are for roof mounting only. Motor and wheel are easily detachable without removing ventilator from curb. Permanently lubricated ball bearings (5BDD10 - 5BDD13) and regreasable pillow block bearings (5BDD15 - 5BDD24). Welded curb cap corners eliminate water entry into ducts or building. Ball bearing motors and variable pitch drives are packed separately when ordered with ventilators.