Primos Mule Deer & BlackTail - 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. Effective for long-range calling Dual-reed assembly for inhale-exhale operation Reproduces throaty grunts and Estrus Bleats by simply inhaling and exhaling Includes built-in compass