Showing its triple extension capabilities
reverser ring in M39, M42 w/ 49 or 52mm FILTER threads
Mounted on camera
Some other uses
Perspective control ring can be mounted in M42 and Nikon mounts.
Universal shift mount . also for ring can be mounted in M42 and Nikon mounts.
Jolos adapters enables uses in several other cameras
Eyepiece for critical focusing . one may use the right user diopter correction lens