Water resistance has been a key selling point for Sony smartphones for the past couple of years, and now the company is highlighting its phones' underwater credentials with a series of quirky new apps. Sony's underwater collection, available in the U.S. on Google Play, showcases ways in which the company's waterproof phones can detect when they're subjected to varying levels of water — from a light rain shower, to being fully submerged. To determine whether the phone is underwater, the apps can emit a high-frequency sound, then use the microphones to detect how that sound resonates, giving an indication of whether it's submerged.