The Olympus OM T2 Ring adapts Olympus OM compatible cameras to a 42mm T-thread.
If you own an Olympus digital camera with a 4/3'rds mount, this T2 ring will not fit your camera, unless you own the MF-1 OM Adapter (OM TO 4/3). There are specific T2 rings available for Olympus 4/3'rds cameras that are considerably less expensive than purchasing the MF-1 adapter, however these are currently available only available in some camera stores.
Additional adapters may be required to complete the connection to telescopes, spotting scopes and microscopes. If you're not sure, ask us.