Kick Port Bass Drum Insert Booster Black

If this thing was only meant for 22" or 24" kick drums, it should have said so in the description. But the manufacturer (Kickport Int. LLC) doesn't mention drum diameter at all.
Their claim it ads punch and low end is completely false, in my experience.
Moreover, the rubber collar mentioned in description and user manual was not included in the package. Instead some flimsy self adhesive foam tape stuff was on the port, supposedly to hold it in place in the resonant head.
Cutting a hole in the head improved the sound a bit to my taste, but adding the Kickport after that (i kept it in place by keeping the hole a few mm smaller than the ridge formed by the self adhesive foam, with some added gaffer tape that did not obstruct the port in any way) made no difference whatsoever. Nada.

A fake product if you ask me, and even if it would work, very poor quality to boot. I'd say it's beneath Thomann to sell this, plus the sound of my Pearl Export 18x16 is hard to improve (which seems like a good thing!). Also from this shop, so no flies on Thomann..