Fourth Element Expedition Duffel BagFourth Element Expedition Duffel Bag Inspired by discussions with some of our more intrepid dive team members who reported that looking for a piece of black dive kit inside a black bag is never easy, but even more frustrating if you are at base camp in a cave system. We developed the fourth element Expedition Series Duffel Bag as a solution to this problem. The blue colour makes it easier to find your kit, bright enough to be found more easily in low