For a fully adjustable, no-nonsense call, look no further than the QuadGrunter 2.0 from Hunters Specialties. The QuadGrunter 2.0 features an adjustable o-ring which gives it the versatility of four calls in one; simply move the o-ring along the soundboard inside the mouthpiece to project mature buck grunts, young buck grunts, doe bleats or fawn bleats.