Cheap arsed mandolin type thing. Yes I know they sometimes have them on the crappy sky gadget shows, but they do work really well. Zips through onions, spuds, etc very quickly and its easy to clean, cost around £10-15, have had ours for around 6 years and its still going strong. Our one is similar to the one in thep ost and we got it from the local market
LINKY to the first place I found