The Power Mule Deer & Blacktail Grunter with built-in compass reproduces throaty grunts and Estrus Bleats with a simple inhale-exhale operation. It is perfect for mule deer and blacktail deer, especially during the rut.Perfect for Mule Deer and Blacktail Grunts and Estrus BleatsEffective for long-range callingDual-reed assembly for inhale-exhale operationReproduces throaty grunts and Estrus Bleats by simply inhaling and exhalingIncludes built-in compassU.S. Patent No. 5,910,039