How are you locking your fifth wheel puck hitch to the bed?

I have a new Curt Q 25 hitch to fit my Ford puck system. I want to replace the wire coupler retainers with locks.

I'm sure others have done this and wondering which locking device you chose.

By the way, the hitch I replaced was a B and W, and I have to say that the Curt Q is one very nice replacement. Well designed and well made. And the puck system is the way to go...so much easier!