Developed in Utah by the Tenkara Guides. The Grave Digger pattern tied with purple "Jamieson's Spindrift" wool yarn, Whiting Brahma hackle & Shetland Sheepdog fur collar, on heavy hooks. The Red Ass Monkey pattern uses red wool. The Utah Killer Bugs are tan with a pink under body of copper & pink head. Proven effective by hundreds of anglers nationwide.