I've used pretty much all of them. If you mean their reeds, then use the pink cross or double red for bugling. I don't like their tone for cow calls much on any of their reeds, they don't allow for a wide enough range of sound. But the Red double is very loud, a real screamer for bugling. Sometimes I can get response on only it, and nothing else. But if you try to cow call with it you'll sound like a cow that got stuck by a porcupine in the mouth. It makes one sound, and one sound only and thats a loud screaming wail. IT does that well. I carry one that I use occasionally for that purpose.
I personally dont think much of their external reed calls. All personal opinion! but, its what works for me.