The C&F Design 4-Row Medium Foam Insert (FSA-2544) is designed to fit perfectly into FFS-M1 housings and secure your flies with Micro Slit Foam technology, which holds hooks firmly without damaging them. Ideal for large dries, nymphs and streamers in sizes #4-10, this insert also offers maximum flexibility thanks to the Foam Changer system, allowing customized organization. Compatible as a spare for other Medium-sized waterproof housings, it is the essential tool for demanding anglers looking for versatility and performance.