hello,
these devices are actually sufficiently well-known and good. But there are points speaking against them! a large and visible external siren statistically even invites burglars to take a closer look at the respective building, as they assume that where there is an alarm, it is really worth breaking in. regarding the window and door contacts: how many ground-level windows and doors actually need to be newly equipped with these contacts? note: the more such contacts, the higher the susceptibility to false alarms or corrosion. do these contacts also constantly and in standby mode transmit to the control center – radio smog? and last but not least: the contacts don’t look particularly nice either ;). i chose the bublitz-b1 system back then, which has innovative technology and meets all requirements without contacts and radio smog. check it out on the internet. there are surely plenty of reviews or press articles about it