Leaked photos and specs gave us our first look at the Amazfit T-Rex Pro 2, a new rugged sports smartwatch that we hope will arrive overnight. The new information comes from 91Mobiles, who have a good track record of targeted leaks. Renderings show a nearly identical design to the original T-Rex, right down to the four triangle screws attached to the bezel and the textured push buttons on the case edges. The only visible difference is the choice of colors, which now include pale grey, dark teal, and black. The real changes are all below the surface, and they look very promising. One of the most impressive improvements is battery life. The first-generation T-Rex can run for 20 hours with GPS and heart rate tracking turned on, but according to leaked data, the new watch will last twice as long. It's a real bonus for outdoor adventures when you're likely to be away from an outlet for days at a time. This improvement appears to be due to Zepp's new optical heart rate monitor, the BioTracker 2 PPG, which reduced overall power consumption by up to 50% in the company's performance tests. The new sensor can also detect signs of atrial fibrillation (irregular heartbeat) and measure blood oxygen saturation (SpO2), bringing the T-Rex Pro in line with Apple, Samsung and Fitbit devices. Many watches and fitness trackers can detect the start of a workout and start tracking it automatically, but the BioTracker 2 PPG can also identify the type of exercise you're doing. We don't know yet how this feature will be implemented, but in theory it can identify 19 different exercise modes, including walking, running, cycling and swimming, which should cover most situations. When it comes to swimming, the T-Rex Pro will also be more waterproof than the original watch, certified for depths of up to 100m instead of 50m, right up there with the Garmin Fenix 6. Good news for divers.