I designed these for a Kala U-Bass, but they could come in handy on any instrument that needs a good thumbrest or a place to attach a strap.

The strap button will need a strong adhesive (such as 3M VHB tape) to stay solid under weight. It works great for my featherweight U-Bass, but may not hold on a heavier instrument—worth a try.

The thumb rests are under much less stress and shear, so something more positionable (such as nano/gecko tape or double-sided foam tape) works great.

Overall, these additions have vastly improved the playability of my U-Bass. Hope they work for you, too.

These print well in both resin and FDM, flat on the plate without supports.