**** It usually takes more than 5 seconds to lock the car with a U-shaped lock, and it takes so much time to drive. And bend down! Sometimes, we just walk away for a while, such as buying a pack of cigarettes and going to WC, really don't want to lock the car. With this alarm, we only need to stretch out our hand, change the password, and press a button!**** You only need to tighten two screws to complete the installation. When using it, you only need to change one or more digits.**** Without battery, you need to buy a 9V battery by yourself. It is recommended to use a battery with better cold resistance in cold areas. When the alarm sound decreases, please replace the battery with a new one. Please remove the battery when not in use for a long time.Operation method:1. Arming, press the red lock button, you will enter the arming state with a beep and start alerting.2. To release the defense, press the unlock button and hear two beeps to release the alarm.