We bought 4 of these for a 2 week break. On opening, they were strongly scented, and we all had high expectations of not being bitten. We each wore them on the wrist, and after 3 days, I had sustained 30 bites, one of which was where just under where the band was worn. On the 4th day, one of our group had a similar number of bites, and a couple of days later, the remaining 2 travellers each had a handful of bites. We each used a 50% DEET spray too, so I think that perhaps despite all precautions, some bugs are resistant to anything used.