Has anyone used a vac pump thats powered by air ? i bought one a fews days ago . waiting until it comes from eerm china .

http://www.ebay.com.au/itm/360351906...84.m1497.l2649

they say it pulls a full vacuum in 2mins ha. cant wait to put vaccy stat on it . are these just the same as a normal 2 stage pump or a little faster? or just crap waste of money?