The Z-Unlimited Add-On For Ultimaker creates unlimited print length. The Z-Unlimited Add-On For Ultimaker is a simple open source add-on that enables your Ultimaker 3D printer to print with an unlimited height. The basic Z-Unlimited package comes with a carriage set and a rail of 1.2 meters. This will extend your print-area 65cm high. You can go even higher if you easily mount extra length of rails to the system.