i use primos hyper single and iv' e tried them all and these work best. last year while hunting it sounded so good a cougar thought i was a elk and charged me and stopped six yards away, i thought i was cat ****, couldnt get the safety of fast enough and luckily he stopped when he saw i wasn' t a elk. the primos bugle with the expandable tube sounds great for bugling also called many bulls in with it last year.