The original diaphragm elk bugle, with two thin reeds. When Wayne Carlton brought diaphragm calling to elk hunting, he had three things in mind...... reliable, realistic and hands free. If you’re going to use diaphragms to call elk you might as well use the ones designed by the man who revolutionized the art of calling elk. The original color coded diaphragm system from Carlton Calls is still the standard by which others are judged.