I acquired my Mammut Nano Eight on eBay from Backcountry Gear in 2014.
The Nano Eight is forged from aluminum alloy and then soft anodized. Mine is 84 mm. tall, 72 mm. wide, and 9 mm. thick. The rope hole is 24 mm. high and 34 mm. wide. The top center thickness is 9 mm. The shaft length and width are 29 mm. and 21 mm., respectively. The eye measures 18 mm. by 14 mm. The ears are 15.2 and 12.6 mm. long. My Nano Eight weighs 40 g.
One side is printed with "MAMMUT" and "NANO EIGHT." The other side is printed with "MAMMUT," a vertical double arrow, "16 kN," a book-with-an-"i" icon, and "1213."
The Nano Eight is a tiny T-side aluminum figure eight with ears. The rope hole is shorter and narrower than normal, so it may provide too much friction on stiff or muddy ropes, if you can get them in the eight at all. Even then, I would not rely on being able to lock off by wrapping around the tiny T-horns. This eight is designed for small, flexible ropes, not normal caving rope.
I suspect that the Nano Eight’s coating would hold up much like a standard eight’s, but once it wore through, there is very little margin for additional wear. Under some horrid caving conditions, I could imagine the eight wearing through and failing in one rappel. I recommend not using this eight on anything except clean, flexible climbing ropes.
The eye is too narrow to accept two full size locking carabiners.
The Nano Eight is tiny so it is obviously lighter than most figure eights with ears; in fact, it is considerably lighter than my smallest deaf eight, the CMI Ultra 8.
Except for very special situations, I recommend choosing another eight and leaving this one in the toy box.