Retevis RT-A1 Children Walkie Talkies 22 Channel FRS/GMRS LCD Display CTCSS Rechargeable Emergency Alert 2 Way Radio for Kids (Yellow,1 Pair) Easy to setup:You can easily change it using the Menu button Have a charger and rechargeable batteries, Easy to connect the charger connector to the charging Keypad lock: Prevent the youngsters from changing the channel and messing with the settings;Adjustable volume level;Allows you to speak and hear at a comfortable volume levels Keypad lock: Prevent the youngsters from changing the channel and messing with the settings Whether how many Retevis RT-A1 Walkie Talkies, it will work as long as the walkie talkies use the same channel