I have the Securam Toplit Electronic Lock on my Liberty Centurion Deluxe 24. The lock works great but, as noted in another review, the 'twist off' collar on the lock can be difficult to turn when it's time to replace the battery. I attribute this to the collar sticking to the rubbery gasket around the back of the collar. What I do is work my thumbnail around the perimeter of the collar (between the collar and the gasket) to slightly separate the gasket from the outside of the collar. Then, while it can still stick a bit, the collar can be twisted counter-clockwise and removed more easily.