【Lens Adapter for GR III】 For use when attaching the wide conversion lens GW-4 or 49mm filters. 【GW-4 Auto-Detection】 Optimizes image stabilization according to the GW-4 focal length and automatically records shooting information to Exif data. 【Filter Diameter】 Allows attachment of 49mm diameter filters. Can also be used for filter work. 【Size】 Maximum diameter: approx. 59.0mm × Length: approx. 23.6mm (excluding partial protrusions), Weight: 11.5g I purchased this for my GR III from the official store, but I have never used it. It is new and unused, but please understand that it has been stored at home, so only those who understand this should purchase it.