This is a complete port & gear set to be used with the Olympus 12-55mm lens.
This Macro Port has a M77 thread, instead of the usual 67mm.It can be used with the Olympus M.Zuiko Digital ED 12-50mm F3.5-6.3 EZ.
If your desire is macro, then you can add the 25103 - Macro Flip Diopter Holder.
This will enable you to use e.g. SubSee lenses (that has a 67mm thread)
Or you can just use the Dyron 77mm diopter if you want to keep it simple!