Phelps Unleashed Bugle Tube Elk Call - The wait is over!!! The unleashed bugle tube is here and ready to rip. Large corrugations in the chamber provide great resonance Corrugations provide structure to the tube 1.25in flared mouth opening for comfort and usability Over-Cupped Exhaust Bell for backpressure and resistance making it easier to use ALL diaphragms Thick walls for extreme volume and NO plastic sound