Linutop OS Pro is already pre-installed on Linutop machine.
Linutop OS Pro can be purchased on USB Key, SD Card or a download on Linutop shop.
Linutop OS Free can be downloaded for free. The Free Version has no limitation, only Linutop Kiosk and linutop Configuration Menu are in demo version most features can be used. (the full version (pro) is available in the Linutop shop) and can be installed. This can be done from the Free system, following the installation documentation.