About this item A PERFECT MATCH FOR YOUR EXERCISE BALL - Fits Best with 55cm, 65cm, and 75cm Exercise Balls - This base adds height to your ball. If you typically use a 65cm ball, we recommend using a 55cm exercise ball. The DYNAPRO Ball Base adds multiple workout options to your exercise ball while keeping it stable and in place. Also great when used as a stability ball chair. QUALITY - No expense spared, we DOUBLED up on the premium material. Weighing in a 4lbs, this Heavyweight more than doubles the weight of any base on the market today. Designed with your safety in mind while exercising and pairing the base with resistance bands. USA Based Team - A rarity in the market today. Need help? Our team is ready to jump in and welcomes the opportunity to connect with you.