Based on Windows 3.0a, and originally called 3.0b, Windows 3.0 with Multimedia Extensions 1.0 was released in October 31, 1991 to support sound cards like the Creative Labs Sound Blaster Pro, as well as CD-ROM drives, which were then becoming increasingly available. This edition was released to Original Equipment Manufacturers (OEMs), mainly CD-ROM drive and sound card manufacturers, and some PCs came preloaded with it. This edition added basic multimedia support for audio input and output, along with new applications: Media Player, CD audio player, more advanced Help format, screen savers, and a new clock. These new features were integrated into Windows 3.1x. Microsoft developed the Windows Sound System sound card specification to complement these extensions. The new features were not accessible in Windows 3.0 Real Mode.