I’m naturally a fidgety person, which is a real problem when my job keeps me in a chair for eight hours a day. By midafternoon, I’m restless, a little stiff, and finding it hard to focus.A small under-desk stepper turned out to be the fix I’d been looking for. It helps me burn off a little excess energy so that I can remain locked in to my work.With the help of Wirecutter staff and a panel of paid testers, I spent several weeks testing 10 steppers. The Sunny Health & Fitness Smart Advanced Stair Exercise Stepper was the clear favorite: It has a bigger step-height range than most steppers we tried, a footpad roomy enough for our tallest testers, and a resistance knob that sits on the front of the machine where you can easily reach it.If you weigh more than 220 pounds or your feet naturally land more than 3 inches apart, the Sunny Health & Fitness 2-in-1 Power Stepper may be a more comfortable choice. It’s rated to hold up to 400 pounds, and its pedals are spaced farther apart, so those with a wider stance won’t feel cramped.