The Stair Bump Aid Kit consists of both the Upper and the Lower Stair bump aid devices. We have found that everyone who orders these products buys them in pairs as a complete kit. We have therefore priced them in kit form to save our customers on both price and shipping. this kit is designed for people who for one reason or another have to go up and down stairs by scooting from one step the the next. The purpose of these devices it to make standing up much easier, both at the landing at the top of the stairs as well as at the bottom.