The Waterworks Lamson Arx Fly Fishing Spare Spool is a great way to seamlessly switch between a Skagit and Scandi set up, or between a double handed set up and a heavy single handed rod, perhaps for saltwater fishing. Constructed with a large arbor, the Lamson ARX spool is designed to retain a variety of lines with both control and reliability. The large arbor design allows for backing, running lines, bulky shooting heads, and sink tips to fit without overcrowding and allow you to fish with ease.