Original Prusa MK3.9 to MK3.9S upgrade kit

The MK4S features a brand new 360° cooling system consisting of a high-performance turbine and a redesigned fan shroud - the result of intensive airflow simulations to ensure that the cold air is directed precisely onto the print. This solution is much more effective compared to blanket fans, because the airflow is not blocked by the print itself. The weight of the Nextruder remains virtually unchanged, but the performance is far better.

Even with the large turbine, the printer is still beautifully quiet and can deliver prints with extreme 75° overhangs. Why does this matter? Because where other printers would already need a hefty amount of supports, the MK4S can easily deliver a beautiful-looking print. Less supports means shorter print times and less material wasted.

The MK4S comes standard with a custom-made high-flow nozzle based on CHT technology. A high-flow nozzle enables faster printing, but also produces more durable prints. Plus, you can get more from the filaments you already know and love - you don’t have to look for any specialized high-flow filaments. Compared to the stock nozzle in the MK4, the new high-flow nozzle delivers between 50 to 114% improved flow rate depending on the material and nozzle diameter. We’re also offering an optional Nextruder nozzle adapter so you can install any kind of V6-compatible nozzle.

Get a quick overview of all your printers, running tasks, and enables you to start, pause and stop prints from anywhere in a nice, clean design. You can also access Printables directly from the app and if a project contains a printable file, simply tap the print button and start printing it right away without the need to use a slicer. The app for iOS and Android is completely optional and is not required to configure your printer. If you prefer simplicity over smart features, you don’t have to install it at all.

The MK4S is compatible with two new optional addons for enthusiasts and modders. First, the GPIO “hackerboard” allows you to control external electronics using G-commands. And we have also introduced an accelerometer addon for those who made extensive changes to the Nextruder. You can find more details on their respective product pages.