Beyerdynamic M 160 by IIRs
These have an unusual shape for ribbon mics, with the diminutive ball end not seeming large enough to contain one ribbon, let alone two.
There is no mistaking the warm ribbon sound however. But unlike some cheaper ribbons I have tried, they don't sound muffled or stodgy: these mics roll off the high end gently as you would expect, and present a much warmer sound than a typical condenser in the same position, but the high end takes EQ well, and a smooth "air" boost can often bring out a beautifully soft and understated top end that you can't really get from condensers. I like to think of this as a matt finish instead of the glossy sheen of a condenser.
The M160 has a slight presence boost in the upper mids, which probably helps it sound sound so great on electric guitar cabs, or drum overheads. This has also worked really well on tricky sources such as a banjo: it captured a perfect balance of transient attack and woody tone, with no unpleasant harshness whatsoever.
In some situations such as solo violin I find I am not so keen on the presence bump, and I tend to reach for the slightly darker sounding M130 instead.
Speaking of the M130, the combination of M160/M130 in Mid/Side is a thing of great beauty on sources such as choirs, string or horn sections... even a full orchestra on a couple of occasions. The small size and light weight is another bonus when positioning them over the conductor's head!
Of course being ribbon mics they have a pretty low output, and will place more demands on your preamps when used at a distance or on quiet acoustic sources. But they are not much harder to drive than many classic dynamic models, and most decent preamps should cope fine. To put it into context, I have often used my M160/M130 mics on location plugged into the Mackie Onyx pres on my firewire interface, and while I have sometimes needed the gain pots up all the way I have never had any issues with noise.
Highly recommended: these mics are a great bargain, and something of an industry secret.