TONGSHUAI roll up doors are lightning quick to open and close many, many times per day, you should never experience workflow slowdown, and should save significant bottom line dollars in total environmental control, no matter what your requirements. TONGSHUAI high-speed roll up doors are designed to seal on all four sides, thus providing a barrier against dust, dirt and contaminants in special applications. TONGSHUAI roll up doors and high speed doors are also designed with total safety in mind. A true soft bottom edge with no rigid bottom bars or weight is recommended so that even if the safety features built into the door should malfunction, the door will still be safe for workers, and products. Please browse our website http://www.commanderdoor.com for more information,or email to me sales@tongshuaidoor.com .Thanks