After installing it occurred to me that perhaps the little membrane patches are meant to be overlaid with a real rubber patch. But since there's no adhesive on tops it doesn't quite computer. Buffed the area well and Applied the first patch to a small well-defined puncture in the tube, installed it into the tire and put it aside for a while. In an hour the tire was flat. Repeated the process and forcefully stitched down the little membrane patch as hard as I could, rolling  between my fingers. Reinflated to 60-actually 50 pounds per square inch and set it aside for 24 hours. Tested the pressure and got a reading of 50. Took the mtn. bike on a 5 mile riide on hard surfaces at speeds up to 25 on descent. Pressure held steady. Decided to check reviews upon my return and was quite concerned about the negatives-which have a high degree of credibility. However my experience so far use okay and I'll go with it and see. Wll update if something changes.