Exakta Extension Tube Focusing Helical

Description

Exakta Extension Tube Focusing Helical. Condition is "Used". Shipped with USPS First Class.
This item can be used with vintage telephoto lenses that required adapters for various cameras. or as an extension tube for close-ups.  It consists of a pair of Exakta adapters that can fit between an Exakta camera and a compatible lens, an extension tube (helical) that can be adjusted in length by twisting the ends (similar to the way you focus a lens), and a short additional tube that fits the threads on the other parts but may not have originally be part of this set.
The various pieces are connected by screw threads that don't seem to be compatible with common threads with which I'm familiar.
Photos are the actual item for sale.
Caliper is used to show approximate size, and is not included in the auction.
Will ship to lower 48 US states only.
Returnable only if description including pictures is incorrect.  Please verify compatibility with your equipment before bidding or purchasing.
Thanks for looking and good luck!