I use one called Crystal Spring from a local health food shop. It's also available on line. You just pop it under the tap and roll it on. Just bought a new one for Ł4.99 but the last one's still got a month or more left and I've had it since September. My OH has used it on occasion when he's run out and says it works well (he's an agricultural engineer so is fairly active). I actually got it because he heard it recommended on the Steve Wright radio show by Janey Lee Grace who's into everything natural.