I’ve tried these on my kids and first thought it worked, but next time we went for a long drive it didn’t work at all. Difficult to really test these things on

I’ve tried these on my kids and first thought it worked, but next time we went for a long drive it didn’t work at all. Difficult to really test these things on kids as sometimes we can drive for hours with no issues, while other times they puke after 20 minutes ...