The Nautilus / Stairmaster 4000PT is the 'original' stepper and has been chosen by more health clubs, medical and rehabilitation facilities than any other stepper. The smooth, rhythmic feel gives users a comfortable, yet highly effective workout. With the great, pre-installed program options users can customize their workout to their personal needs regardless of the users age or fitness level. The 400PT's patented, independent pedal geometry assures safe, biomechanically correct movement and the electromagnetic brake precisely controls pedal descent from 26 to 138 steps a minute.