hello. the adapter can work with a nikon af-s dx nikkor 35mm f/1.8g to 6d mark 2 

Yes. I have the same lens and adaptor on my Sony a7ll and it works beautifully. The m42 is also known as the 'universal' mount as other 3rd party camera and lenses also used it. I own 6 other K&F e-mount adaptors to different lens makers (ltm, MD, CF/CD, Nikon) and they all are well built with a nice snug fit. Highly recommended. 

20mm is the size of the watch band if you want to order a replacement band. I replaced the band with a magnetic one soon after I bought it. I love this watch and have had it going on 2 years. Good luck and hope I answered your question. 

I actually have not received this adapter yet. It's shipping from China. Don't think that was disclosed in the ad. However, I do not believe this is for the Pentax Q body rather for digital and film cameras that take the Pentax K mount in its many variations. So I'm expecting to be able to mount my Leica M mount lenses on my digital and film Pentax K mount cameras, no autofocus or relay of exposure information, only to be used with manual focus and exposure. 

HI your fujinon m42 55mm 1.8 and a sigma-z m42 135mm 2.8 are M42 mount, the item can fit your camera and lens