Hi There is a lot of choice out there but despite other posts wireless systems these days are as good ,if not better than earlier wired systems, for domestic use. They feature 3yr battery life with battery monitoring,antijam reporting and support Pir's, door reed contacts,vibration analysers,smoke detection and even water level monitoring. They also have full tamper protection built in. Whilst others on group will no doubt argue the ins and outs of radio as a security medium IME having fitted 100's of radio systems in my years have had very few instances of radio interference/jamming etc. Yes the early systems were sometimes poor but the new systems are a lot better and have full EU & BS accreditation. There are still some cheap and cheerful systems out there for around £100 but that goes for wired systems as well. Like anything else these days "you gets wot you pays for" so whatever you decide pick a reliable supplier. HTH CJ