Wench® style duck calls have the patented "Tone Ridges" and "Tuning Ditches" on the sounding board which keep the reeds from sticking or freezing while giving the call its raspy highs and lows. Tuning hole in stopper/bell allows you to vary pitch.
The tone is just right for a double reed call. It takes a bit of practice to get the feed call rolling . And dont give it too much air on the hi-ball . Even when your not perfect the quakers will give you a look-see.