I read some Amazon reviews and corrosion or dirt in the lock or sides of the unit were the biggest reasons for low scores. Numerous people said they couldn't remove the cover or pull out the unit to use the hitch. It had a greater number of positive feedback but I'm skeptical.

I couldn't find how secure the combination lock is. It looks like a luggage style lock and those can be opened with minimal practice.

I would look to finding a different location on your vehicle.

Is your key small enough to fit in a prescription bottle to keep it from breaking? I've also seen a number of containers in dollar stores a key could be slipped into.