Bought 3 of these to attach implement tags. First, there are 2 VERY sharp spikes that press against the tire during installation. The idea is that if someone tries to tow or drive without removing it, it will result in the tire blowing out. Unfortunately, they're also long enough to make mounting the device difficult, even on a medium-sized tire and rim. When I pushed on the yoke these spikes started to press into my tires! I decided to take a jigsaw (with a suitable metal blade) and just cut the pieces off. Now everything fits perfectly and I think it's an equally good theft deterrent. It's also worth noting that the locks have different keys from device to device, making them more secure than some other cheap models with the same keys.