Product needs a bit of adjustment to get it to adhere to the surface of the bass ( in my case, a typical gloss poly body finish), as was explained by your instructions.
The trick is to get the right amount of moisture under the suction cups and let it dry sufficiently (a day or two for me). After that, it is now very solid. My only gripe is that the surface of the product is a bit too slick for my preferences. It was easily solved by using an adhesive pick grip sticker on it.
Best part is the adjustabilty. I can place it exactly where I want it. I've tried many thumb rests, this is finally what I've been looking for...and no installing screws! I just ordered a couple more. 5 Stars!
Don't be like me, I didn't read the website correctly. I have an ash bodied bass, and the Thumb Fin wouldn't adhere to the body. Thumb Fin sent to me some contact paper and the Thumb Fin now works a dream. My friend who is a professional bass player was also super impressed.
Therefore if you have an ash/wood bodied bass order contact paper when you order you Thumb Fin.
The thumb fin has an attractive appearance, and in principal looked like it should have worked: but unfortunately the sucked do not adhere to my varnished ash solid body bass ukulele. I think that the would be perfect for a more traditional gloss finished bass.
Great product! It took a few days for me to figure out exactly where I like it positioned. It would be nice if it were a little thinner, but I bet it has to be that size in order to have big enough plungers that will stick. One recommendation: clean the pickgaurd around were you want it with alcohol first. Also make sure the plungers are clean—but don’t use alcohol on those, just soap and water.