The Loop Opti 180 Dry Fly Box has individual compartments that make storing your favorite patterns easy. The slotted silicone grooves on the other side of the box make for a quick swap of your favorite patterns that hold securely. Organizing your favorite patterns for a day on the river is a breeze with this boxes capacity to hold 170 single flies. If you are working to eliminate excess boxes or gear in your bag this box is just the ticket. Organize your box to fit any day on the river. It is an effective carrying solution for you your favorite selected patterns for any day on the water.