This fly was first developed by the Tenkara Guides in Salt Lake City. It's a variation of the Sawyer's Killer Bug, developed by Frank Sawyer. Frank was the riverkeeper on the Wiltshire Avon, where a part of his duty was to control the population of grayling.
These flies are only available individually in sizes 12, 14, 16 & 18. Just click on "add to cart" and then adjust the quantity in your cart.