Not my first adapter from K&F, love those russian vintage lenses so I use a lot of adapters since I dont want to swap adapters all the time. I also have Nikon and Canon adapters to adapt for my Fuji mirrorless. Never had a problem.Perfect adapter, nothing else to add.
Excellent mount. Well designed and constructed. Fit is secure and does not allow any wiggling/movement. Have used it successfully to mount Helios and other classic MF2 lenses on my X-T1 and X-E1. A must have to maximize the use of legacy lenses on your x mount camera.
it's nicely made but beware - if you have the M42 adapter they don't provide an allen key to enable you to adjust the lens rotation so that the aperture info is on the top of the lens. None of my allen keys fit as the adjustment screws are too small.