This large vacuum unit is designed to give maximum rouging speed of about 1000CFM throughout a large range of vacuum pressure with a large GKT 500C backing pump for the beggining roughimg staged then acompanied by a RNVB 21.20 1000 Booster to allow pumping speed to remain at the 1000 mark as we reach the lower pressures. Ideal for smaller cross sections of pipeline that would not takes pumping speeds of higher speeds.