Size: 28 mm / approx 1.1/8 in Hook: J:son SS.DF #10
The largest J:son imitations of mayflies are tied to perfection. Mayfly Dun Size 1 imitates mayflies such as the Green Drake and similar large sized mayflies.
We do recommend you to use a J:son Swivel for all your fly fishing and all your flies. However, it is necessary to use a J:son Swivel whenever you are fishing a J:son fly in size 1 or 2.