Pretty much all I use. I have a grown a preference to bugling bull diapharms in the past few years..thanks to elknuts suggestion. Funny I used to think the hootchie mama was the bomb and while it worked a few years ago...man can you tell that thing a mile away. It seems every elk hunter owns one in my neck of the woods. Slowly I might add, I have come to the realization when it comes to produced vocalization reeds/squeeze calls are to mono-toned and lack the ability to sound real. Just personal opinion or thoughts here.
May not be the biggest/badest elk but called this sat 5x out to the open field to get a shot 10 days after season had been open. The herd moved off before legal so all I could was call and hope I sounded like a different herd..result a notched elk tag and meat for the freezer. I'd say it worked JFL.
A little practice and finding the right one, your set!!! Good Luck