Wireless instruction system. The transmission distance is more than 280 meters in open field without interference. This instruction set consists of: - A blue WHIS transmitter and receiver. - A 220 v duo charger. with which both WHIS devices can be charged at the same time. - A small and discreet clip-on microphone with integrated noise cancellation. - An in-ear headset, easy and hygienic to apply behind the pinna and suitable for each ear. - A spare earphone.