Sure. Do I think these are the best locks around? Not necessarily but most locks are beatable with a bit of effort and sometimes very little effort, however the key convenience is very nice. With 4 trailers plus a few other locks it is very helpful for me.
The lock I use for the Demco couplers is called the coupler pin lock, but I also use their hitch pin lock, a couple of their cable locks, a cylinder lock for my toolbox in the back of the truck and even one of their padlocks. One key that I have with me all the time fits them all. In any case here is the link to their website but they can be found elsewhere.
We make Breakthrough One-Key Lock Technology, so you can set all your locks & keep everything conveniently secure with one key.
www.boltlock.com