Hunters Specialties Cow & Calf Tone Trough Elk Diaphragm Calls. Its a revolution in elk diaphragm calling says Wayne Carlton. The built-in sound chamber or tone trough allows hunters to blow the call using less pressure while achieving great sounds. Every Tone Trough call is made using high-quality Infinity Latex which is easy to blow and has superior durability to all other types of latex on the market. And because less pressure is required the life of both the reed and the call is prolonged. Equipped with a Premium Flex frame to ensure consistent fit and stretch from call to call Tone Troughs sound chamber produces the highest pitched elk bugles and most authentic nasally cow calls on the market. Specifications for Hunters Specialties Cow & Calf Tone Trough Elk Diaphragm Call: Manufacturer: Hunters Specialties Species: Cow Country of Origin: USA Package Contents: Hunters Specialties Cow & Calf Tone Trough Elk Diaphragm Call Hunters Specialties HS-WCC-70805: Cow & Calf Tone Trough Elk Diaphragm Calls