Experience Triple Brown Power. The Herd Bull Triple Reed is one of the strongest, loudest, most durable elk diaphragms ever built. It produces deep, nasally cow calls and loud, deep-tone elk bugles. Blow as hard as you want and it will keep on blowing. Its three thin reeds withstand the stress of mixing it up with the most aggressive bulls. Made from durable Infinity Latex®, it absorbs significantly less moisture for the longest-lasting performance. If you’re going to use diaphragms to call elk, use the ones designed by the man who revolutionized the art of calling elk.