ncludes circuit-size (28. 5 L x 14. 5 W x 4 H) grey aerobic platform and black risers Platform features grooved, nonslip top and supports up to 275 lbs. Four nonskid feet on each riser and platform prevents sliding or scratching floors Vary workout difficulty by adjusting platform height from 4 to 6 using risers Set includes a grey nonslip platform and two original black risers to create the foundation of any workout program