ST-868 Interphone is a new model of intercom with earphone that can be used for poker gamble tricks.
When one guy speaks in one room with the interphone and signal Transmitter, you can hear the voice secretly with the related earpiece. There is also a signal receiver for the earpiece. They can have a distance of 100cm between the earphone and the signal receiver. And with the earpiece, you can hear the voice as far as from 50m.
This system of ST-868 Interphone and earpiece works very well with the high performance batteries for the earphone, interphone and signal receiver.
The earpiece can be adjustable with different frequency so as to get the voice from the related interphone. Also you can adjust it to get the best voice.