These lights were a lifesaver for our stairs! I have 15 steps, so 3 lights were perfect. One at the top, one in the middle at the landing and one at the bottom. Really easy to install using the adhesive patches that came with the lights. Approaching the stairs in the dark the bottom light activates, and as I go up 3-4 stairs the middle light activates, then up another 3-4 stairs and the top activates. Lights stay on long enough for you to get up and down the stairs with no problems. I rated it 4 stars only because the lights have been turning on during the day when they are walked by, draining the batteries sooner. [This review was collected as part of a promotion.]