Sonitus Acoustics The Kicker 2.0 22"x18" Pillow

the sound is great, simple and efficient. It had a great impact on the sound of my kick.
My only gripe is if you transport your bass drum vertically in a bag or a case, the pillow tends to fall inside the drum. A simple velcro attachement option that would be included in the package would probably solve this pesky issue. That's what I did personally, I put 2 stripes of velcro inside the shell and on the pillow and the Kicker doesn't move anymore. But even if it is sandwiched between the 2 skin, it's not enough to keep it in place during transport.
Other than that, 100% recommended, as you can put a flat boundary mic on it. I would recommend the Thomann one. Very good mic for the price. You should see my review on it :)

The product rotates within the bass drum of my Gretsch Renown.
After a few minutes of playing the kicker has moved sideways in my drum.
It doesn't change the heard sound, but changes the recorded sound as the mic position changes.
I sent Sonitus an email on 4th of July, they answered the same day asking me to measure my drum and the kicker, i did so and sent them all the requested information, since then not heard a word from them, three emails and multiple phone calls where not answered (today is the 24th of august) , i am stuck with a product that doesn't work and the manufacturer doesn't answer emails.