is a free, open-source 3D viewer for PCB designs (used with ECAD software like Altium, Eagle, KiCad, etc.). It does not require a license key — it's distributed freely under the GNU General Public License (GPL).
The license key unlocks several professional-grade tools beyond the basic viewer: Get The ZofzPCB Premium Features License zofzpcb license key
: For secure corporate environments where internet access is blocked, a USB Security Dongle is a free, open-source 3D viewer for PCB