Download of 20-sim Pro 2.3 was on the developer's website when we last checked. We cannot confirm if there is a free download of this software available. 20-sim Pro lies within Photo & Graphics Tools, more precisely 3D Design.
The program's installer is commonly called 20SIM.EXE or 20sim23.exe etc. We recommend checking the downloaded files with any free antivirus. The actual developer of the software is Controllab Products B.V. The following versions: 4.1 and 2.3 are the most frequently downloaded ones by the program users.
From the developer:
20-sim Pro allows you and your colleagues to view and simulate 20-sim models. A new and powerful software that you can get it at a low price. An easy to use software for all users.
This is the full demonstration version of 20-sim 4.0 Pro. This means that all 20-sim toolboxes and libraries are available, and there are no restrictions on the number of submodels or states, except that you can not store models.
You may want to check out more software, such as BenVista PhotoZoom Pro, Tech-Pro World Clock or K-Lite Pro, which might be related to 20-sim Pro.