The wobble cushion or stability cushion is an ideal tool for improving balance and posture, Coordination and Flexibility. It is good for active sitting, muscle strengthening, joint stabilization. Use the free pump for easy inflation or deflation, and adjust the pressure to the desired firmness. Instruction: Insert the needle of the pump into the tiny hole for inflation; Insert the needle only without the barrel of the pump into the hole for deflation. Find the hole on the 4th outer ring--One spiky dimple is replaced by that tiny hole. Seller Warranty----Replacement & Refund: Should pump be faulty or cushion defective, please "Contact Seller" directly (other than Amazon Customer Service) from Amazon Buyer Central against this order for a replacement or refund. Seller aims to provide hassle-free after-sales service and usually replies most emails in 12 hours.