Review on 🚲 Crankbrothers Gem Hand Pump - Dual Piston Pump for Presta and Schrader Valves, Short/Long Design, High Volume and High Pressure for Cycling Enthusiasts by Chase Steele

Excellent pump. Very compact and I love the ability to switch from high volume to high pressure while pumping. One thing to note is that when you switch from Shredder to Presta, there are actually two parts that need to be pulled out and rotated. If you just flip the rubber piece over, it won't be deep enough to latch onto the presta valve. It's not very clear from the instructions. I almost returned the pump before realizing what was going on.