Nikon Speedlight SB-800 variable the focal length is about

the focal length is about 267mm

This helicoid extension tube lets you seamlessly adjust magnification for close-up work with your Pentax 67 and nearly any Pentax 67 lens (not included)

and practical also

and the unusual spherical aberration control ring allows more control over image quality

Nikon Speedlight SB-800 variable the focal length is aboutThe Nikon Speedlight SB 800 is a professional on camera flash that provides full manual control on or off camera, plus full TTL cabability on Nikon DLSRs. The SB 800 has a tilting swiveling zooming head, a PC sync connector, and Commander capability with compatible cameras and Speedlights. Some cosmetic wear, good function. Includes case, diffuser, and "5th battery" compartment.