Exped Fold Drybags use mid-weight fabric to balance durability with weight. The BS or Bright Sight version comes in a bold colour making it much easier to locate in your pack or in the tent at night.
Exped says:
Fold Drybags that stand out; BS stands for Bright Sight. They share the same excellent materials and features of our standard Fold Drybags. Made for those who need the visibility or want to extend their collection of dry bags.
Exped's Fold Drybag BS come in a few guises - this 'BS' or Bright Sight version is tougher than ultralight but still doesn't weigh very much. These 70D bags are best used as general purpose drybags - but with the added benefit of being easy to see and locate due to the bright colour. You can pack these, throw them in your rucksack, pull them out at camp and not worry about them as they are really hard wearing.