A versatile fly patch with a Foam Changer that can be worn around the neck. Easily remove and store the system foam from a Boat Box or System Case, and wear it on your chest for convenience. You don't have to prepare different flies for wading or boating. The "ultimate system" of freely interchanging System Foam from the Boat Box/Universal System Fly Case/System Fly Patch can be set up. Comes with a neck strap that can be applied in two-point and one-point configurations. The Standard Foam Changer allows you to keep frequently used flies easily accessible on your chest. Includes one Standard System Foam size (L size: 8 rows/M size: 6 rows/S size: 5 rows). This is a hanging fly patch, and does not include any pins or other fixing tools.