Look for this!

Here's what the American College of Sports Medicine says to look for when selecting a stair stepper:
• Rails: Your stepper should have side rails, a rail in the front, and/or moving posts on the sides to help you keep your balance.
• Smooth, independent stepping action: Pushing one step down shouldn't push the other up. Dependent step platforms (pushing one step down moves the other up) don't work both legs as well.
• Safety: Solid construction and a stable frame are important, so the unit won't tip over. • Electronic display: Your stair-stepper's computer console should, at minimum, display heart rate, calories burned, distance climbed, rate of speed, and intensity level. You can buy stair steppers with more sophisticated training programs, but you don't really need those for a basic exercise routine.