These are the Activskin A876 support footless tights with a fly. I have had these for a couple of years, and usually wear them running when the temperatures are in the 40's and low 50's. I have also worn them cycling with temps in the 50's. They are opaque, but just sheer enough that they shouldn't be worn without something under or over them. They were great for running today with temps in the low 40's which felt like a heat wave. I almost wore sheer hosiery, but figured I would give these a run so that I could also review them. They are very durable, and will probably last almost as long as a regular pair of spandex tights. They are available through Activskin at www.glieberman.com/footless/ .