Matador, King of Compaction, has added the Droplet to its growing list of items that unfold from really small to really useful. Have you seen their Pocket Blanket? It condenses a 55" x 44" swath of ground cover into a 4.8-ounce, 4" x 3" pouch. Similarly, the Droplet squishes a 9" x 10.5" wet/dry bag into a tiny silicone container the size of a keychain. You can even use it as a keychain if you want.
The Droplet serves two purposes: 1) Keep wet stuff contained; 2) Keep dry stuff safe. Use it to store wet swimsuits or sweaty gym clothes and block them from mucking up your car or duffel bag. Use it to store your phone, cash, cards, watch, etc. while you're swimming, at the beach, or stand up paddleboarding and create a barrier between them and damaging water/sand. Matador also recommends a Droplet for travelers who want to secure toiletries that might leak in a suitcase, as well as for eaters of snacks that could create a mess in briefcases or backpacks.