Pro Series Exercise Ball Slow Deflate Red 55 cm Jobst Opaque 30 40mmHg Knee 155 kgs Maximum Overall Length Style:Pair (Left & Right) 155 kgs Maximum Overall Length * Aluminum casted back release hinge allows back to fold down for easy storage and transport * Standard rear wheel locks * Overall width w 17 seat: 20 (open) 9 (closed) * Overall height: 39 Excellent Retail Packaging * This ball was specially designed to deflate slowly if punctured thereby reducing risk of injury * Provides improved stability at the points of body contact and enhanced performance due to the responsive surface design * Comfortable to sit on * Great grip thanks to built in latitudinal ridges and an outstanding texture that doesn t feel like plastic * Comes with two plugs an inflation adapter a measuring tape to help insure proper inflation and a poster detailing 24 exercises