Angler Sport Group Easy Grip Slit Foam Flybox - Our most popular fly boxes feature EasyGrip foam. The box is made from high-grade polypropylene with no sharp edges, corners or protrusions. Engineered with a double living hinge and positive latch. EasyGrip Foam has slits that act as fly keepers and small cutouts to guide your flies into each slit. Holds large numbers of flies with no damage to the foam. EasyGrip Foam in Base and Lid. High-grade polypropylene Foam in Base and Lid