The TLM170r is a multi-pattern medium-diaphragm condenser microphone with a smooth and natural frequency response. TLM stands for TransformerLess Microphone (and the 170 was the first made, I believe, correct me if I’m wrong) and the “r” signifies the modern version which can be connected to a remote phantom power supply that can be used to switch pickup patterns remotely. This would be great for orchestral or drum overhead work where switching pickup pattern would be a pain.
I recently purchased a TLM170r as a flexible addition to my TLM193. The 170 is essentially a 193 with a variable pickup pattern (also a 10dB pad and a lowcut). This extra functionality adds a lot of extra cost to the microphone! I can now record in M/S with the two TLMs.

TLM170 in fig8, with a TLM193 beneath. Setting up for M/S recording of Classical Guitar.
The TLM170 contains a medium-sized capsule like the TLM193 (often assumed to be an LDC as it looks like familiar Neumann LDCs…). This means it’s off-axis pickup, sensitivity, transient response and proximity affect (in cardioid mode at least) are somewhere between an LDC and SDC – the effect of this that it has a pretty good sensitivity with low noise floor, reasonable off-axis sound coloration but can get a little boomy if miking too close. This makes it excellent at a bit of a distance. As the proximity effect extends higher in frequency than an LDC, on the right (higher tonality) voice it can be very warm, but on a deeper voice that extra warmth in the 150-250Hz range can be really boomy and unnatural. All of this is the same as the TLM193. Although I haven’t tried this much yet (just once), I would hope that switching the 170 into Omni would calm the proximity affect somewhat and would make it more suited to deeper voices.
I have used the 170 as a fig8 side mic in MS configuration on Classical guitar and also as drum overheads (in cardioid) along with the 193. Both have worked exactly as expected – thick, natural and detailed sound!
I bought the mic second hand but it is a shame it is so expensive. Not because it is not worth the money but I imagine most people looking for a professional workhorse multi-pattern microphone will be much more drawn to the AKG C414 due to it’s significantly lower price (1/3 price) – the 170 (in my experience, and according to published graphs) is so much flatter and more natural so really great for Classical recording…