As mentioned on the page for the Commodore 710, the CBM-II models were Commodore's last effort to capture the business market with its superior proprietary technology. All machines in this series are characterized by the MOS 6509 processor, Commodore BASIC 4.0, the Commodore "SID" sound chip, IEEE-488 connectivity, an RS232-C port, and the ability to display 80 columns of text.

The Commodore B500 as it is displayed in the museum is considered a prototype CBM-II model. These machines are part of the "low profile" CBM-II series, named as such because they feature a single integrated unit with a full business keyboard, numeric keypad, and 12 function keys.

There are 2 known versions. One version with 128K, with 64K allocated for BASIC code and 64K for variables, and one version with 256K memory, where the last 3 banks of 64K memory are used for variable storage.

The model owned by the museum has a very low serial number. From the stories, it is believed that this unit was likely sent to the Netherlands by Commodore to familiarize themselves with the machine and provide support to customers who purchased a CBM-II. The CBM-II series did not become a great success, making these models very rare.