1.【Three different tones】The whistle as an emergency signal, 3-tone function: tone 1/tone 2/tone 3 with switch.  The electronic whistle with lanyard are designed with 3 different tones. You can choose the sound that best suits your needs to make better use of the electronic whistles. 2.【Durable】: The electronic whistles made of high quality ABS material are durable and sturdy, non-toxic, tasteless and no harm to you. You can use it for a long time with confidence. Each electronic whistle comes with 4 pieces CR2032 batteries for your use and replacement. （Note: This battery is not rechargeable）. 3.【Easy to use, one-button operation】 It is not too big, fits strongly in the hand, can also disappear in the training jacket pocket, you need to check where the whistle button is located. 4.【Wide application】 Electronic whistle suitable for referees, trainers, teachers, ball games and boating, running, animal training, camping and other outdoor activities. 5.【Hand whistle with lanyard】Comes with removable hand strap lanyard. Small and easy to carry. One-handed operation, easy and convenient, batteries included. Do not use the electronic whistle too close to your ears to avoid damage to the auditory nerve, and do not use it in small spaces such as rooms, venues, etc.