... the completed-closed cover is waterproof, dustproof. Features 1. Mobile (trailer) type, completely closed structure, waterproof, dustproof, move easy. ... absorber, braking system and steel welding of entire trailer guarantee 60km/h speed. 3. Dealing with unqualified ... high vacuum states, low noise, working reliable. Advantages Mobile(trailer) type, completely closed structure, waterproof, dustproof, it ...