For Full Size 4/3 Mount. (This Fits Olympus "E" Series) A "T-Ring" couples your SLR or DSLR camera body to a T-Adapter or other "T" threaded camera mount.
This is a 37mm Deep T2 Ring (Fits Olympus PEN & OM-D Series) (Fits Panasonic Lumix G Series) - This “T-Ring” will couple your Mirrorless Camera to any T-Threaded Mount. The thread on this ring is Female 42mm (.75). Note that T-Rings for Mirrorless models are actually tubes, rather than rings.
This is a Wide (48mm) Low Profile T-Ring. It offers a wider light path to reduce vignetting and a shorter light path for more back-focus. A standard T-Ring for Micro 4/3 is ~37mm Deep. This Low Profile Ring is only ~10mm deep.. giving you an extra inch of Back-Fous.
This is a 37mm Deep T2 Ring. The threading is 48mm (0.75) for Wide Format T-Adapters Only. Fits All Micro 4/3 Mirrorless Cameras. This “T-Ring” will couple your Mirrorless Camera to any 48mm Threaded Mount. The thread on this ring is Female 48mm (.75). Note that T-Rings for Mirrorless models are actually tubes.