My Sister and I both play Bass (and guitar), I have
Big hands and hers are small, so the Thumbfin works awesome for both of use because we share all of our equipment!!!!!!
Using on a Hofner 500/1. The pickup position doesn't leave a lot of room to rest the hand. The comfort and playability are much improved with the Thumb Fin. Would give this product a 4.5 if able. Will consider addition for other basses.
Maybe explore some optional colors - black, white, silver?
If you can't find a suitable place to rest your thumb, this gives a very single and effective solution. Easy to move about and cash be removed at any time, all without any permanent change to the bass guitar body
So far so good. Sometimes it comes off but generally the suction holds.