I bought the M42 to Fujifilm (FX) adapter for a bunch of old M42 lenses I had lying around. Honestly blown away by the quality if this product. It seems like it's all metal, the build quality is very good. The packaging is nice and good for storage.$25CAD just gave me access to 4 new prime lenses for my favourite fuji cameras. Great product.
This little adapter has allowed me to use a couple of my father's vintage lenses on my Fujifilm X-T1. It's a well made bit of kit for the money. I have now ordered a couple more vintage lenses to give me a complementary set alongside my Samyang and Fujinon lenses. When some pretty tidy vintage lenses can be picked up for 30 quid each or cheaper, experimentation in manual focusing is within reach of everyone. Focus peaking on mirrorless cameras helps a great deal too. Highly recommended.