Features: 1. The throttle will be automatically locked when there is no remote signal or the RC car runs out of control range, thus protect the car from crash. 2. The throttle will be automatically locked if the receiving battery voltage is below 2.9V. 3. The throttle lock position is settable. 4. It is suitable for various kinds of RC cars. 5. Made of quality materials, which make it safe and durable for long term use. Direction for Use: 1. If green light is on, it indicates that RC car is working normally. 2. When there is no remote signal or the RC car runs out of control range, the red light will be on and the throttle will be automatically locked. 3. The green light will be on after remote signal recovered, then your RC car can work normally. 4. Throttle lock position setting: when the green light is on, put the throttle into the position where you want it to memorize, and then press the button. After 3 times flash of the red light, current throttle lock position has been memorized. 5. When receiver voltage is below 2.9V, throttle will be automatically locked and the red light will be on for a long time. Replace with new batteries, the throttle will be unlocked. Specifications: Condition: 100% Brand New Item Type: RC Accessory Material: Plastic + Metal Color: Black Size: Approx. 37 * 21 * 9mm / 1.46 * 0.83 * 0.35inch Weight: Approx. 8g Operating Voltage: 4.8-6V Operating Current: 7mA(4.8V) Package Include: 1 x RC Fail Safe