Byron have been supplying doorbells for over 100 years and wireless systems for over 15 years. Most of their products operate in the 434MHz range (so they are generally less expensive) and they offer unique products such as mechanical wireless bell units as well as more familiar chimes. They offer both plug-in and battery powered units, twin and triple packs with ranges of between 50m and 200m and volumes between 80dB and 90dB. Some models vibrate and others have strobe lights to help the heard of hearing or for noisy environments