Cybertron Satellite - Mito Matrix (LE 200) - Transformers Accessories Accessories I don't know who Mito Prime is, but it's a matrix for MP-10 and keychain.
I think the "functional" means it can fit in MP-10. But yeah, misleading. I would expect a "functional" Matrix to be able to open, at least. ... well, actually, I would expect a "functional" Matrix to destroy Unicron. But... yeah.
Lucky me I don't own MP10 and I already have the Matrix from the Battle in Space set! Or 20 or so other perfectly good Matrixes that came with various figures over the years. Why would anyone want to pay 55 bucks for this?...
Well now there's a black and clear version too... Cybertron Satellite - Mito Matrix (Black & Clear) - Transformers Accessories Accessories I kind of like it, but yeah not for these prices. I'll just stick with my battle in space matrix.
The black-and-clear version is unlikely to be the Mito Matrix. There are fourteen of these differently-coloured Matrices, which are being offered in stores with the Cybertron Satellite display in Japan. Each one corresponds to the colours of a "Town Commander" - fourteen 'bots named after the region they're the mascot of, as "[Region] Prime". Mito Prime is the Town Commander for Mito, and that purple and gold "Mito Matrix" is his - it was available in November. This black and clear one is the next one released, now, in December, and is probably the Fukutsu Matrix, belonging to Fukutsu Prime.