microSD
Secure Digital (SD) is a proprietary hardware, proprietary, non-volatile memory, non-volatile, flash memory card format developed by the SD Association (SDA). Owing to their compact size, SD cards have been widely adopted in a variety of port ...
memory card
A memory card is an electronic data storage device used for storing digital information, typically using flash memory. These are commonly used in digital portable electronic devices, such as digital cameras as well as in many early games conso ...
MP3
MP3 (formally MPEG-1 Audio Layer III or MPEG-2 Audio Layer III) is a coding format for digital audio developed largely by the Fraunhofer Society in Germany under the lead of Karlheinz Brandenburg. It was designed to greatly reduce the amount ...
format. They were first available at
Wal-Mart
Walmart Inc. (; formerly Wal-Mart Stores, Inc.) is an American multinational retail corporation that operates a chain of hypermarkets (also called supercenters), discount department stores, and grocery stores in the United States and 23 other ...
and
Best Buy
Best Buy Co., Inc. is an American multinational consumer electronics retailer headquartered in Richfield, Minnesota. Originally founded by Richard M. Schulze and James Wheeler in 1966 as an audio specialty store called Sound of Music, it was r ...
stores in October 2008. The selection of songs came from
Universal Music Group
Universal Music Group N.V. (often abbreviated as UMG and referred to as Universal Music Group or Universal Music) is a Netherlands, Dutch–United States, American multinational Music industry, music corporation under Law of the Netherlands, ...
,
Sony BMG
Sony BMG Music Entertainment was an American record company owned as a 50–50 joint venture between Sony Corporation of America and Bertelsmann. The venture's successor, the revived Sony Music, is wholly owned by Sony, following their buyout o ...
,
Warner Music Group
Warner Music Group Corp., commonly abbreviated as WMG, is an American Multinational corporation, multinational entertainment and record label Conglomerate (company), conglomerate headquartered in New York City. It is one of the "Record label#M ...
and
EMI Music
EMI Group Limited (formerly EMI Group plc until 2007; originally an initialism for Electric and Musical Industries, also referred to as EMI Records or simply EMI) was a British Transnational corporation, transnational Conglomerate (company), c ...
. As of mid-2011, SanDisk's website listed a total of 14 albums available in the SlotMusic format.
The audio files contain no
digital rights management
Digital rights management (DRM) is the management of legal access to digital content. Various tools or technological protection measures, such as access control technologies, can restrict the use of proprietary hardware and copyrighted works. DRM ...
, and are encoded at minimum
bitrate
In telecommunications and computing, bit rate (bitrate or as a variable ''R'') is the number of bits that are conveyed or processed per unit of time.
The bit rate is expressed in the unit bit per second (symbol: bit/s), often in conjunction ...
s of 256 to 320 kbit/s.
A slotMusic albums may also include high-quality images and videos in multiple formats. The contents of each microSD card may be altered by the user, enabling them to add or remove files from the slotMusic card as desired. Another type of card,
slotRadio
slotRadio was a proprietary format developed by SanDisk that delivered music on a microSD memory card. Up to 1,000 songs were preloaded on microSD cards which were protected with digital rights management. Users had no direct access to the musi ...
, was developed in 2009 which had radio-like controls. A slotRadio card had more restrictions on how it worked, such as not being able to backtrack to a previous song.