These slim silicone fly boxes are thin enough to fit in a shirt pocket, yet large enough to hold 91 flies that are tied on hooks up to size 1. The slotted silicone back on these boxes hold flies firmly, and is self healing so they will not come loose or damage the liner with extended use. You can poke the silicone with hooks all day long and it will not damage the silicone as it self heals. One other great feature is these are waterproof and will keep your flies dry if you accidently drop the box in the water. These boxes are perfect for nymphs and small streamers. Great for minimalist fishing where you dont want to take a ton of gear. Just slip this into a shirt or pants pocket, grab your fly rod and some nippers and go out and fish. Or you can put multiple boxes in your fly pack and organize your flies to type with many boxes.