Because of its robust appearance, the CAT S31 is also known as the Hulk among smartphones. Thanks to the sturdy, metal casing, the device can take a beating. In addition, the phone has an IP68 certification, making it completely dust and waterproof. This allows the CAT S31 to survive a heavy rain shower and even lets it take photos under water. You can also take photos and selfies on dry land with the 8-megapixel rear camera and the 2-megapixel front camera. Do you wear gloves when you're at the gym or at work? Good news, because you don't need to take them off while using this phone. In addition, Wet Touch Technology allows you to operate the device when your fingers or the screen are wet.