This is a specialized M42 mount adapter that features an integrated optical element (lens) with a fully manual aperture range from f/4.5 to f/22. This type of adapter is typically used as a teleconverter or a corrective mount to allow M42 screw-mount lenses to achieve infinity focus on modern DSLR systems (like Nikon F). Complete with its original protective end caps and factory box, this item is in excellent condition consistent with careful use. A great tool for optical enthusiasts and vintage lens photographers looking for precise manual control.

• Mount Type: M42 Screw Mount (Universal)

• Aperture Range: Manual f/4.5 – f/22

• Optics: Integrated glass element for focus correction/magnification

• Condition: Used - Excellent; includes original box and front/rear caps

• Features: Manual aperture ring and all-metal construction

• Origin: Imported Japan