The Speck Call is designed for maximum volume and minimal back pressure. Since you are not having to use your hand to choke the exhaust down to create back pressure, you have more control of the call. Designed to mimic the high pitch yodels and clucks of a modified Olt T-20, this call is capable of turning those "Tar-Bellies" from long range and has a great murmur and low end to keep them searching for you all the way to your gun barrel.