Adjustable parking assist lines and full view screen help you to reverse easily and safely. ? Loop Recording & Accident Lock: Because of dashcam rear and front seamless loop recording function, the newest recorded video will overwrite the oldest video when sd card is full(except the locked file), and the current video will be automatically locked once the dash cam W/G-sensor detects shaking or collision to prevent it from being overwritten by loop recording and saved in the event folder for easy viewing.