The device also features 3 convenient to use buttons for guide screening and simple pairing modes. The smoke detector head is usually swapped out for compatible Synergy+ heat detector heads making it easy to meet up with prerequisites. Remember to Observe, this product or service is for indoor use only. https://www.thesafetycentre.co.uk/blog/ems-wireless-firecell-systems-from-the-safety-centre/