After my car transporter trailer was stolen I decided to upgrade my anti-theft device. They are so easy to use. Insert and turn the key to release the lock cylinder and it will pop out. Put the keys back in your pocket. Slide the two halves far enough to go through the hoop. Place the tyre/wheel and join the two halves together as tightly as possible. Then press the lock cylinder down, slide the plastic protective cap over the lock cylinder, done. I believe ANY lock you put in place can be picked. It's just a deterrent, if someone wants your trailer they can and will get it. I use this in conjunction with a trailer hitch. I also sometimes lock my safety chains after wrapping them around the hitch. This should prevent the safety chains from pulling your trailer when the hitch is locked. I like the good visibility of it. It's very noticeable. I hope the thieves just walk away when they see this.