Production description The raw material of tg turbine ventilations: Tg turbine ventilations are made of the stainless steel We use the advanced ubc bearings from the usa Features: 1.Do not need electric force 2) protection against high temperature, bad air environment 3) anti-corrosion, anti-acids and bases, anti-oxidation 4) long usage. The ball diameter is 420mm and the throat diameter is 300mm.