maximum range of 200m (in open field) silver / anthracite , black transmitter variable volume control of about 70 to 90 dB ( A) 8 melodies (call differentiation ) ON / OFF switch wall mounting Warning light (red LED) with weaker batteries Transmitter Hoseproof IP55 with nameplate and LED function indicator incl. 1 x 3V CR2032 battery Receivers Batteries not included (4 x 1.5 V LR6 / AA ) 256 radio frequencies with self-learning coding Dimensions: 120 x 120 x 28 recipients mm / transmitter 34 x 96 x 20 mm Color : silver / anthracite, black transmitter Compatible / upgradeable with all HX devices This wireless chime set is also suitable for connection to an existing doorbell system