A Maximum of 4 units will work on one system
Unfortunately old models of Door Chimes work on a fixed frequency which is unique to the units that you have purchased. It is not possible to add or replace either the Bell Push or the Receivers. Old models are not compatible with the MiP System. You can choose from the pre-made collections (single/double/triple) or you can mix and match if you require extra bell pushed, or you want a mix of different colours, to do so, just purchase the chimes and bell pushes separately.Chime size approximately 9.5cm Long, 3cm Thick
Bell push size approximately 8.5cm long , 2cm Thick
LUCKARM Wireless Digital Doorbell With 25 Soft Melody Receiver & Bell PushWater proof design for the remote control button
Maximum 150 m operating range allow the house user truly satisfy for the doorbell performance.
Digital coding - 315/433.94 MHZ with strong anti-interference system prevents the doorbell from interferences outside or between neighbors
Energy saving design-the battery inside the button can last for one year(20 presses per day)
Suitable to install at dwelling house,office ,hotel ,shop,tire building and factory etc.