The Caterpillar CAT S31 is a military-grade tough phone that can handle tough environments and extreme temperatures. The display is covered by scratch-resistant glass and the chassis is dust, drop and waterproof. This smartphone has Android on board so you can download new apps from the Play Store. There is an 8-megapixel camera as well as a front-facing 2-megapixel lens so you can capture superb photos. The phone includes 4G, Wi-Fi and GPS and the internal memory can be boosted with a microSD Card.