... problemHow to use the medical device1, connect the sender with the brief2, Turn on the receiver system, ... be different according to distance between receiver and sender.How to test the medical deviceTouch the two ... will have music quickly.Kits:One receiver, one sender, two sensor briefsRemark: if receiver has no LED ... The receiver has two 1.5V battery, the sender has one 12V battery, users can also order ...