I bought a pair of this tights along with a top of the same type. The fabric is a high-tech sort of poly that is very thin, light, silky, and fairly warm for the weight. The top already has several runs and snags after only a few uses as night-wear. The pants do not yet have any problems but with the poor durability of the top, I'm pretty sure they too will snag and run easily. I'm not a fan of the silk-like feel of these but mostly I'm disappointed with how easily the top was damaged. I have several other synthetic base layer garments and all have stood up to years of use with admirable durability.  These are an exception and I wouldn't buy either the top or pants again.