Hunters Specialties Slingblade Box Calls. s Calls Tone Trough diaphragm line. "It's 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 Trough?s sound chamber produces the highest pitched elk bugles and most authentic nasally cow calls on the market.The Cow & Calf call has one and a half reeds for the most realistic young cow moos and calf vocalizations. Specifications for Hunters Specialties Slingblade Box Call: Manufacturer: Hunters Specialties Color: Brown Package Contents: Hunters Specialties Slingblade Boxer Call Hunters Specialties HS-STR-100038: Slingblade Box Calls