The attached hand pump lets you inflate, and deflate, to your liking, at will. If you want the lumbar support to be firmer and/or larger, you have simply to squeeze and release the hand pump bulb, until the desired firmness and size is obtained.If later, you want it less firm, and/or smaller in size , you have merely to hit the release valve button on the hand pump bulb. Air will escape, and the support will decrease in size and firmness,just a superior lumbar support.