We don't recommend ordering Barebone system (without memory and storage), as it has dual board which may cause complication to assemble it.
We, Winston Marriot Ltd, are not associated with Windows, pfSense, Ubuntu, CentOS and other software vendors etc. We are hardware manufacturer, and our devices are compatible with many Operating Systems, open source & licensed softwares and firewalls; for example, Windows, pfSense, Ubuntu, OPNSense, CentOS, FreeBSD, Linux etc. We only provide Installation service of Free trial/demo Edition of softwares and open source firewalls upon request with our hardware. Please contact the software provider directly to purchase any license. We do not commercially distribute any OS or Firewall except Windows (Licensed versions).