Hand Key Oscillator Automatic Key Trainer Controller Adjust Transmission SpeedHand Key Oscillator Automatic Key Trainer Automatic Key Controller Can Adjust The Transmission Speed CW keyer: This is a two in one CW keyer that can be used as a keyer or a key trainer. When used as a key trainer, it supports both hand and automatic keys. Features: 1. It is about the same size as an ordinary eraser, but thinner than an eraser. Its extremely small size makes it extremely portable, and it can be put in a pencil case, school bag,