Trailer coupler lock are a great way to keep your RV safe. This is especially important if you have kids or pets who might wander off. When you unhook your trailer from the tow vehicle, you need to make sure that the lock on the coupler is engaged. This will ensure that it doesn't get towed away without you being able to get it back. There are two types of trailer coupler locks: manual and automatic. The automatic ones work with a keypad, and the manual ones require you to use a key to unlock them. To make sure your trailer is always locked, make sure to keep the key in a safe place and store it out of reach of children or pets. And, if you ever lose the key, don't worry - there are plenty of places where you can buy replacement keys online.