The WSN-OLYC-T2-2 is an adapter ring that connects to industry standard "T-2 Mount" threads and provides an Olympus 4/3 mount on its opposite side. It is used often to connect Olympus E series digital SLR cameras to SPOT Imaging Solutions' digital SLR/large format camera couplers.

Its "T-2 Mount thread" is a screw mount using a male M42x0.75 metric thread.  The adapter ring is made of black anodized aluminum.