DMM.co.jp (FANZA) – The primary distributor for these label codes.
R18.com – The English-language storefront for many Japanese digital labels. CJOD-350-MR.mp4
The .mp4 extension indicates a standard MPEG-4 digital video file, likely a web-rip or a direct download from a digital storefront. CJOD-350-MR.mp4
While specific cast details for the "350" entry can vary by the exact sub-label, videos under this label code generally feature: CJOD-350-MR.mp4
You can typically verify the exact cast and plot by searching the code on Japanese database sites or retailers such as: