Another type of video media, CRVdisc, or "Component Recordable Video Disc" were available for a short time, mostly to professionals. Developed by Sony, CRVdiscs resemble early PC CD-ROM caddies with a disc inside resembling a full-sized LD. CRVdiscs were blank, write-once, read-many media that could be recorded once on each side. CRVdiscs were used largely for backup storage in professional/commercial applications