(Now they hitch a ride on the seams of nylon luggage.) Feather beds are much more expensive than down-filled duvets or comforters. They are a heavier construction. So if you live in a damp climate without central heating, it may suit you to use the feather bed as a warm covering. If, on the other hand, you live in a place with all the modern conveniences, it would be better used it to even out a lumpy or hard matress.
Sometimes the liquid contact indicators are placed in such a way that they can be inspected from the outside. For instance there is a LCI in the headphone connector, the dock connector, and near the SIM-card slot of an Apple iPhone.
Despite the iPhone's new water resistance, Apple notes that liquid damage is not covered under warranty. iPhone 7 and iPhone 7 Plus are splash, water, and dust resistant and were tested under controlled laboratory conditions with a rating of IP67 under IEC standard 60529.