While machined shims are the gold standard for dimensional accuracy and precision, they are very expensive.
A problem with 3D printed shims, is that most are made out of PETG and the variability in thickness of the shims can be as high as 50 to 60 microns, which for many optical systems can introduce tilt.
These shims are printed out of Polycarbonate infused with carbon fiber (PCCF) so not only are they stronger than softer materials, they are also more precise. I’ve measured dozens of my PCCF shims with a micrometer, and while I don’t guarantee this I will state that most shims are within 10 to 20 microns of variability in thickness. This tighter tolerance will have less of a negative impact tilt.
This is a complete set with the following sizes: 0.3mm, 0.4mm, 0.5mm, 0.6mm, 0.7mm, 0.8mm, 0.9mm, 1.0mm and 2.0mm.
Available in M42, M48, M54, M68, AP 2.7″ and AP 3.5″.