A beta test where the manufacturer invites the public to participate. Typically, a beta version of the software, which times out (stops working) after a certain period of time can be downloaded. In exchange for this, the user is expected to provide the manufacturer with feedback on the software’s stability and functionality.
Public beta tests allow the manufacturer to have their pre-release software tested in true real-world situations, by actual users in the field. The user gets an advance look at an upcoming software update, and gets to actively partipate in the development of that update.
The trade-off is that the software is beta-level, and may not be as bug-free as the final release software. However, in most cases, software made available for public beta is very near to being ready for release and is generally stable.