Yellow Sally stonefly nymphs are available much of the year, but more active during warm summer months. RIO's My Gal Sal is the perfect imitation of this natural, with a pale golden yellow belly covered by a dark brown and copper back tied on a barbless Gamakatsu hook with a tungsten bead.

The following are the bead sizes per hook: 

Size 14 - 3.3 mm 

Size 16 - 2.8 mm