Anonymous7 months ago000So it's not really clear - if I want 3 alarms connected together (if one sounds, so do the others) what's the cheapest thing to buy?Show in original language (French)Anonymous7 months ago • purchased this product-101purchased this product Helpful answerThis one fits. But you also need the radio module: Ei Electronics radio module incl. 10-year batteryUnfortunately, this is not "cheap".Show in original language (German)CommentAnonymous7 months ago000Thanks, but do you need that many modules per alarm?Show in original language (French)Comment2 comments