Have you lost the transmitter? No problem, it is possible to purchase the transmitter separately. 
 
Please note:
Before you start using the new transmitter, you must pair it with the receiver. (Pairing)
 
Pairing the transmitter with the receiver:
Place the transmitter and the new receiver on the table in front of you. Press the volume button and the music button on the receiver simultaneously for 3 seconds. (i.e. the 2 outer buttons).
 
Then test the device by holding a metal object against both push buttons of the transmitter. (a knife or scissors) If the transmitter and receiver are paired correctly, an alarm is triggered immediately. The set is then ready for use.