I bought these because for running. I usually run before the sun is out, but sometimes I finish after it is out. I run up and down hills, so my only concern was that they would stay steady. The clarity is impeccable and they did stay pretty firm on mya face. They didn't bounce around and need adjustment. Very good quality, too. I have have used them only a few times and keep them in their case when not in use, but they seem quite durable.