Shelf stereo

A shelf stereo, also compact stereo, micro component system or mini component system, is a type of home audio product. Shelf stereos are typically both small enough to fit on an average shelf (hence their name) and sold with all of their necessary components packaged together, if not outright integrated into the same physical enclosure. For example, a shelf stereo featuring CD playback will include (at a minimum) a CD drive, a digital-to-analog converter, an amplifier, and at least one speaker, making it capable of playing CDs out of the box without the consumer needing to purchase or connect additional equipment. Shelf stereos exist for many different types of audio media, such as CDs, AM or FM radio, cassettes, vinyl records and digital music files from an MP3 CD, thumb drive, or Bluetooth device, and many modern systems will play back multiple such types.
Boomboxes can technically be considered shelf stereos, but are usually not marketed as such. A device marketed as a shelf stereo will, for example, almost never accept battery power or incorporate a carrying handle, while nearly all boomboxes do both. Conversely, a device marketed as a boombox will almost never feature detachable speakers, while many shelf stereos will. Single-purpose Bluetooth speakers are subject to a similar consideration and will, similarly, rarely be grouped with shelf stereos despite meeting the strict definition (although many systems playing back, for example, CDs or radio will incorporate supplementary Bluetooth connectivity and still be sold as shelf stereos). 
History.
Shelf stereos date back to the radio receivers often found in diners ever since the advent of radio. However, these early receivers were not stereophonic receivers. They have more stereos to add Bluetooth or Wi-Fi network connection. 
Today.
In terms of amplifier power, many shelf stereo systems have a total system power greater than 500 watts, which is considerably more than many surround sound receivers, which are usually higher in price. Most shelf stereos use either the standard two channel format or the 2.1 channel format (which includes a subwoofer), with the latter being more common in the higher powered systems. The "point one" indicates the use of a subwoofer along with the two main speakers.
However, this is the main difference between shelf stereos and surround sound receivers. Surround sound receivers most commonly use 2.1, 5.1, 6.1, and 7.1 speaker setups that provide true surround sound. Shelf stereos can accept different types of media. Many stereos come with or have the ability to connect:
The size of 2010-era shelf stereos has also changed. Many of the popular stereos are one connected piece as opposed to multiple speakers that separate from a main unit. Among the new one-piece shelf stereos are the stand-alone iPod speaker system. These systems are made primarily for the use of iPods and utilize an iPod dock. With the "vinyl revival", more modern systems are available with turntables, a feature which largely disappeared from shelf stereos in the 1990s.