This is a 10mm F2 prime lens for X-mount. Purchased in June and used only a few times indoors for test shots, it's in like-new condition. Purchased from Kouten Koubou. Please refer to the following for specifications: https://www.stkb.jp/smartphone/detail.html?id=000000001958&category_code=ct1482&sort=order&page=1 Focal length... ~10mm Maximum aperture... 1.5~2 Other features... Lens hood included, front lens cap included, rear lens cap included