I've been calling coyotes for over 20yrs, and using Knight & Hale calls for over 15yrs, and I'm definitely not impressed with the new line-up of these translucent bodied calls.
I purchased the new K&H Ultimate Predator I, Jackrabbit, and Cottontail.
Ultimately, I have mixed feelings about the Cottontail call. It works well enough, and has good volume, but this K&H Cottontail call is very high pitched for a cottontail distress call. It sounds more like a rodent distress call. It actually works fairly well as a coyote pup distress call, since it's so high pitched, and has very little rasp. It DOES work, and has reasonable volume. I used this call to bring it 2 coyotes on the first night I tried it out.
On the other hand, the body is very weak, I had these calls in the bottom of my pack and actually broke the mouthpiece of the Jackrabbit call (had to get a new one).
For what it's worth, it works, but there are far better cottontail distress calls out there.