This is all he really says about the mic:
"My microphone system was built using 2 AKG CK-1 condenser microphone modules.
A DC Fet microphone pre-amplifier designed by Mr. Akihiko Kaneda, the famous Japanese amateur amplifi er designer, is attached just below the CK-1 condenser module.
This micorphone system is powered by batteries and looks like a kind of robot.
Since the angle between the two condenser module is 90 degrees, it acts as a one-point-stereo microphone."
And then there's some more stuff about it here:
http://www.kcc.go.kr/~jhlee/dcmike.html