Ltpgtthis works in combination with lightwaverf heating switch to provide a fully remote controlled heating system simply replace existing radiator valve without any plumbing or draining of system this can be controlled by pc or smartphone when used with the wifi link controllerltpgtltpgtampnbspltpgtltulgtltligt3v dc requires 2 x aa batteriesltligtltligtdownload lightwaverrf app from your app storeltligtltligtrf frequency 868mhzltligtlt