It is not possible to use the plungers to stick to a matte surface , so the company has a small piece of contact paper they provide that can allow you to stick your Thumb Fin to a matte surface. I trimmed the piece of contact paper so that it would look more attractive and there wouldn't be a bunch of contact paper sticking out around the sides. Worked well. I am very happy and I have these on three of my bass guitars
I have tendonitis in my thumb from years of playing in a rock band that requires fast pumping 8th notes all night. When I saw this thing, I thought maybe it will help, as when I play a 5 string, and I'm primarily using the 4th string, I use the 5th string as a thumb rest and it seems to give my thumb a break.
I've only had the thumb fin a couple of weeks but so far so good! I found it very comfortable on the past few shows. It'll probably take a few more months to know whether it helps sort out my tendonitis.
If you're looking for a non-mod and easily adjustable thumb rest, you can't go wrong with Thumb Fin. I've been using it for up to a week now and I haven't had any issues with the suction cups. I highly recommend this!
I am a newbie bass player (at 66) so I haven't really settled into the best thumb position yet. The suction cup adhesion method (which holds very well) of Thumb Fin allows me to move around a bit to find the best location and angle for me without drilling holes or otherwise marring my guitar. I am very happy with the purchase.
