A beta prototype is typically an augmentation of an alpha...

A beta prototype is typically an augmentation of an alpha prototype – meaning it has all the functions in place that are expected for the final product. The beta prototype also has fewer flaws than the alpha prototype.
Beta testing is usually shorter than alpha testing. The reason for this is that the beta testing is usually designed to identify the minute, last-minute issues before the envisioned product is launched in the market to the actual consumers