This transmitter box doesn't come with batteries, antenna, servos, receiver, receiver battery, or transmitter crystal. None of this is needed in order to use the trainer capability. The "Student" box gets its power from the "Teacher" or master radio. Requires a trainer cord: Trainer cord: Square to Round use number FUTM4420, Square to Square use FUTM4415. DOES NOT INCLUDE INSTRUCTIONS ... the instructions on usage and hook- up are in the manual of the radio being used for the "Teacher" radio. The trainer box is equipped with a square plug receptacle.