got bitten a lot in and heard about the silk sheets from other travellers. have i been lucky since or the sheets are helping? don't know but the idea is that since silk is tighter wowen, it's supposed to be more difficult for them to penetrate and also to get traction but you still need to air them in the sun regularly and it doesn't mean they can't find their way around the sac either. no guarantees but still comfy (-: