Okay, I can't figure out what this thing is

I recently purchased a Kiev 30 and got into 16mm photography. The sets go for reasonable sorts of prices on eBay - I've had a lot of fun with it so far, picture quality is far better than I expected. But one of the accessories that came with it...I cant for the life of me figure out what it does.
See the attached picture from ebay: The black reel sort of thing in the bottom left of the picture.
I started out under the assumption that it was a development reel, but I cant figure out how it would work. Maybe a tool for loading the film into the cartridges? Measuring tool? Time Machine?

I suppose I can get by fine without it, but the curiosity is driving me slightly mad. I look to you, APUG, to help me sleep easier at night.

This 'black reel sort of thing' looks very much like the top reel from old soviet tank, the missing bottom reel has spiral. This particular top reel looks like modified to sink much further down towards bottom spiral to accommodate 16mm film.
These one-spiral tanks were pretty highly regarded being easier to load and clean compared to two-spiral models.

My Stainless Steel 16mm reels are like that, with the spiral on only one side.
Jobo made 16mm reels, if you already have other Jobo stuff you might want to check that out.

Aha! that makes perfect sense now, it's half of the equation. I hadnt heard much about the 16mm development options, I just kinda dunked the first few rolls in a tank loose. Something I need to look into, thank you for the advice.

These tanks are quite common here and can be obtained for a buck or two. Shipping costs will be higher, i guess I may hunt down one for you.