txhunter58---I personally use the tone converter one for the hyper lip single, I also use my hand over it from time to time depending on the sound I'm working. The hyper lip double is just flat too loud for most calling sequences.
To be honest, the best videos for the use and all the sounds needed are on our videos.
Vol-1-2-3-and 4 show the many uses and situations using the hyper lip single. Vol-4 shows the use and all sounds of the Cow - Calf call and the hoochie mamma.

NwOutdoorshop---The cow call by Carlton "estrus whine" is identical to the hyper lip single in sounds. there are times when a different cow call can strike a special cord with a particular bull, but not very often, the real key to a calls effectivness is in the user more so than the brand of the call. I say this because of how many different styles I've used over the years, you can spook elk or you can call them in with any good call. The key too is knowing what you're saying, or responding to an elks response correctly, not just spitting out the only sounds you're familiar with, and hope for the best!! elknut1