The Rockin' R, while very similar to the Mondo series of calls, is uniquely based on the way Jimbo likes to set up one of his old black calls. With a tapered mouthpiece that takes away backpressure but allows the caller more versatility of air delivery depending on what sounds they are trying to achieve. Along with that, he opened up and tapered the bore on the insert adding a touch more volume on top but also to be very loose on the bottom. Like the Mondo series, Jimbo went back to an original keyhole and worked forward to develop a smoother top end with lots of punch but also retain that signature rattle. He was looking for a separate shape that honored the classic look of a reversed Olt and his RNT Roots but also stood on its own. So with the help of John Stephens making sense of his crude drawing, what you see as the Rockin' R came to life. The Rockin' R Logo evolved to what you see on the call with the help of Blake Fisher's creative talent using Jim's initials, JR.