Special electronic whistle for coaches and instructors for outdoor use Plastic electronic whistleABS shell with rope strapFunction:-Anti-crack design-Two sound effects to choose from, one is the same sound as an ordinary referee whistle and the other is a "beep-beep" sound, similar to the sound of an ambulance horn. The new product is equipped with 3 sounds, suitable for different occasions, outdoor rescue, traffic police directing traffic, referees, instructors and coaches, training competitions, suitable for training pets, pigeons : take off, power on, return home.- Loud volume, good effect- Portable, greatly increase the distance from the ear and reduce hearing damage!- 4 CR2032 button batteries (batteries not included) Breaking with the traditional way of whistle with the mouth, it adopts electronic sound production. Two different sounds can be played by directly pressing the button. The design is beautiful and the sound is no different from traditional sound. It is user-friendly. Note: The data are all measured manually, please allow 1-3cm error, due to the difference in light and display, there will be a certain color difference, the actual item received shall prevail.