This is a 2-in-1 CW keyer that can be used as a keyer or a key trainer, and when used as a key trainer, it supports both hand and automatic keys. The product is multi-functional, both a stand-alone version of the practitioner, directly plug the key can be practiced. It is also an automatic key controller that can be connected to radio stations, Automatic keys, hand keys support single-machine practice. Practice transmission speed can be adjusted. Press and hold the button, press the key, adjust the transmission speed! The interface of the product is 3.5mm. The product uses electronic power supply, easy to carry and use. The product consumes very little energy. Note:Due to different production batches, there are differences in printing/appearance, which does not affect use. Power Supply:1 x button battery(Not included batteries) Colour:Green Material:PCB Package Contents: 1 * CW Trainer Only the above package content, other products are not included. Note: Light reflection and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.