We recently reviewed Amphipod waistpack hydration systems and after testing extensively in the scorching weather for a full month with Amphipod handheld hydration systems, we have decided to write a follow-up review. We tested out four of Amphipod’s latest handheld systems: Hydraform Thermal-Lite™ (12oz and 20oz), Hydraform Handheld Pocket™ (20oz), and PURErun Handheld™ (16oz). All…