The adapters contain no optical lenses (model dependent) to degrade your lens' optical qualities.
The side of the adapter that mounts on the camera utilizes a solid, high-quality finish, and high-precision brass mount while the lens mount is made from high-quality anodized aluminum alloy. 
The adapters utilize either a screw or a button to secure the lens firmly (model dependent). 
Infinity focus is maintained by all adapters.

Made in Japan.

1 YEAR WARRANTY

Limitation:

NO AF function or confirmation.

Apply Aperture Priority mode or Manuel ONLY.