โบลเวอร์ 

CONSTRUCTIONS: blowers pffer a unique design resulting in a blower with one moving part - which means more-up time and lower maintenance. Long-life shielded bearings are mounted on both sides of the impeller and outside of the pumping chamber, providing Highter pressure ratios, Cooler running bearings, Longer maintenance, 100% Oil-free air, No vibration and therefore complete dynamic stability. http://getadsonline.com/0/posts/3-Services/27-Other/30441--.html