After writing my review about this alarm, and messing around with the lock some more because I spent enough money on it to where I really, really would like for it to do its job, I would like to add 3 more stars to the review. This is why. The alarm comes with a soft black base for the lock that 'connects' to the macbook and ensures fit. However, I removed this, and the lock did NOT warp the side cover! I figured it was warping before because of poor fit, so I put the black base back and really pressed it harder (not too hard) into the lock, and twisted the lock, and voila! Lock fit perfectly without extreme warping. I will no longer resell this item. Thank God for curiosity and perseverance...and now, I can say with confidence--this lock!
(Still a little bitter about the plastic around the lock hole warping though.. My $1500 Macbook looks not so $1500. =( But learn and move on. =D)
--old review--
I agree with some people's review of Kensington alarms for Macbooks, although I wish I've read them before purchasing this lock. It did warp the plastic side and took me a while to lock/unlock it. The 1 Star is for at least making a nice alarmed lock for Laptops, but I was sorely disappointed when the plastic would warp every time I put the lock on my Macbook. Unfortunately, I need it for the cruise I'm going on next week, but am going to re-sell it as "used" and "anti-Macbook 13" when I come back home. If you own a Macbook 13" Series, it seems, so far, that Kensington locks are not recommended for you.