arfur, you need the biggest compressor that will run on a plug 13a, i recommend also not to run it through a extension lead, look at spending around £450-500, those with small tanks are just not good enough, they will be just running and running all time trying to catch up with the tornado, compressors, the motor turns a pump, very similar to a engine, the pump sucks air in through a filter, then, in a very similar fashion to a engine the piston forces the air into the tank, there is a valve that lets the air only flow one way [ two actually but lets not get too technical] into the tank, when the desired pressure is reached in the tank a the compressor turns off, when the pressure drops the compressor starts again automatically, a small cheap compressor will soon burn out, a full size proper one will last years and years and ALWAYS have a value .