Today, we’re reviewing the latest batch of water-resistant and waterproof earphones from four different companies. Three of the earphones compete directly against one another: H2O Audio’s Flex ($30) and Dry Corp’s Dry Buds 100% Waterproof Headphones ($30) are extremely affordable options from established makers of waterproof cases, both silicone-tipped canalphones stripped bare of frills in order to hit their price points. By comparison,…