Hi, we use Sainsbury's enhanced healing waterproof film dressings (pack of 5). They're like Tegaderm but, for us, easier to get. The padded central part doesn't stop the sensors being scanned. We sometimes change it after swimming to prevent any water from slackening the dressing or sensor off if it's been on a few days already but they do the trick. We use one all the time as the sensor can sit proud on a little arm and my daughter's hair is long and got wrapped round it otherwise. Hope that helps.