All items from the HX system are compatible with each other and can be freely supplemented and expanded. The HX Twin wireless doorbell set is a value set consisting of 2 receivers and one transmitter. One of the receivers is portable and features a belt clip. The stationary receiver has a plug-in connection. The HX system includes an easy-to-use self-learning function for adding additional components. To extend the range, one or more range extenders can be connected. Additional transmitters such as the HX wireless motion detector or the HX wireless passage detector can also be integrated into the system. To avoid interference with other wireless transmitters, the HX system offers 256 frequencies that the device learns automatically. The HX Twin wireless doorbell set includes a weatherproof transmitter (IP44) with a nameplate, which is splash-proof and already comes with a battery. Volume control: the volume of the chimes is approximately 82 dB. The chimes can play 8 different melodies. Installation: The portable chime features a wall mount with a belt clip for easy installation, while the stationary chime simply needs to be plugged into an outlet. Call differentiation: When using additional transmitters, a different melody can be assigned to each transmitter (e.g., front door/back door). Visual call signal: Along with the melody, a visual call signal appears in the form of a red light (portable receiver).