We get them from the camping stores. We have a few assorted sizes and weights (lightweight versus durable). They are pretty cheap. Ocean Research durable ones cost a bit more but they're great. We will put our cameras and phones in whilst on boat trips or on the beach. We've also used them for our cameras and belongings for on water rides such as Grizzly River Run and Splash Mountain. We even use them as lunch bags for work every day... Versatile little things.