Some of us laughed, some of us celebrated—and some of us wished we’d had this device in college. The Flow Meter is a digital gauge that mounts in your hose and measures both how much you’ve drunk and how many ounces are left in your keg, er, reservoir. No more running out of fluids just when you’re getting thirsty! An advanced mode (who knew?) also lets you enter the amount you want to imbibe, then monitors your progress and estimates the ETA to an empty bladder.
Skip the confusing owners manual and follow these directions (courtesy of a call to customer service): Hold both buttons down to get started, switch modes with the top button, and toggle numbers with the right. Runs on a watch battery (included). Breathalyzer not included. $30 (also available preinstalled in a CamelBak reservoir); 1 oz.; camelbak.com.