This is possibly my favorite purchase of the last year. We have a beach condo and also often vacation in tropical locations. Every time we want to go on a walk along the beach without pockets or dunk into the surf or pool, I anxiously glance back at our pile of towels (in which we hide our phones and keys etc) to make sure everything is still there. Now we don't have to worry so much. On a recent vacation to Mexico, we used this safe every day. Threaded it through our beach bag and around the lounger or table legs and felt more secure leaving it. I'm sure someone could cut the cable if they had the right tool, but why bother when you can go to the next lounger more easily.
I should say it is much bigger than I anticipated. At first I was worried about getting it in my carry on but then just stuffed socks in there to maximize space. It can easily hold several smartphones and a wallet or two.