Simply The Best In Custom Calls Grand National and World Calling Champion, Billy Yargus, has teamed up with WoodHaven to introduce his new Blue Vyper Signature Call. The Blue Vyper is a 2 reed call made with clear latex. The Blue Vyper features a unique V-cut design with each corner wing slightly trimmed to deliver tremendous calling versatility. This diaphragm call delivers smooth, soft calls with little effort, as well as cutts and cackles with backbone, and a clear front rolling into raspy yelps.