Rapha, nice but a bit pricey?

I'm thinking of getting some nanoflex knee warners - are they pretty good and grippy? I have skinny legs and so some I've tried don't really stay where there supposed to be.

And what's this space age warmth / rain prevention material like? Does it work?

They seem grippy enough on my legs. As I mentioned mine cover from above my knee right down to a few inches above my ankle. I wear 3/4 bibs so these overlap on the knees giving extra protection. Worth the investment imo.