The LSD-2 is comprised of two separate dual-membrane solid state microphones contained within a single housing. Its capsules are mounted in close proximity on a vertical axis - the upper capsule assembly having the ability to rotate 270 degrees horizontally, relative to the lower capsule. Two C&K three-way switches control the polar response, high pass filtering and -10dB pad for each capsule (The switches on the front of the body correspond to the lower fixed capsule, while the switches 180° opposite on the back of the mic control the rotating upper capsule). It is the combination of capsule articulation and independent pattern switching which allows a user of the LSD2 to achieve all manner of coincident pair stereophonic recording techniques. Due to the close proximity of the capsules, there is no phase cancellation resulting from time delay between the two signals. This translates into excellent mono compatibility.

Point: Locals might like to look here.

Point: The Microphone University at DPA is a good reference if a little biased to their product range. Also see tonmeister.ca and the Stanford 192a site.

Disclosure: I have a couple of B3's that I absolutely love and they were very nicely priced. Recommended (as Jerry Pournelle used to say in Byte).