FROM THE MANUFACTURER This stacker is the most durable on the market, most often you will find thin plastic and attached with sticky strips of tape. The j/fit stacker is so strong that small screws are included to hold the ends securely in place for a long lasting highly stable ring. One stacker must be used for the base and then one additional stacker is used between the balls. The stackers are so strong that you can stack several balls on top of each other (with a stacker in between)

Perfect for high traffic gym use; Holds any size stability ball in place. Two small screws included to attach the ends for a strong, durable, stable ring. Heavy-duty long lasting plexiglass construction; Extra-strong construction will not allow sides to cave-in.

Date First Available: January 22, 2013. Best Sellers Rank: #863,514 in Sports & Outdoors. Customer Reviews: 3.3 out of 5 stars 4 ratings 3.3 out of 5 stars. : B00B4RW5K6. Sport Type: ?Fitness. Size: ?39x4-Inch. Part Number: ?10-0901. Manufacturer: ?j/fit. Color: ?Clear. Brand Name: ?JFIT. Package Weight: ?0.6 Pounds. Item Package Dimensions L x W x H: ?41.5 x 5.5 x 0.1 inches.