I learned off the same video that's posted. They sound a little better as the slate gets worn in. IMO a nail call's clucks and purrs are excellent, but the yelps are only fair. I hate practicing them indoors because they have such a piercing pitch, but I know there are some birds that like that. I have one in my arsenal this year. But, if it doesn't start getting results, I may move on to other calls in the future.