BondTech Prusa I3 MK2.5S / MK3S Mosquito

Upgrade your extruder to a Bondtech Mini Geared with higher gear ratio – 3:1 – that allows for extra push force and higher resolution.

Use a lightweight extruder that will allow your 3D printer to print faster or to achieve better surface quality.

Decrease the risk of heat creep to avoid clogs and improve filament feeding to avoid slipping and deformation that cause under and over extrusion issues.

This is a Bondtech upgrade for the popular Prusa I3 MK3S and MK2.5S that will allow the use of the world acclaimed Mosquito hotends.

This kit contains the necessary parts to convert your current extruder to our own popular design based upon our BMG (Bondtech Mini Geared) extruder with 3:1 gearing ratio for better precision and resolution together with optimized geometry for the heatsink cooling and professional SLS 3D printed housing.

This extruder upgrade presents the following main features:

• Adapted to fit Prusa’s new filament sensor and Mosquito hotends;
• Includes one Bondtech’s BMG extruder with 3:1 gearing ratio;
• Optimized geometry for heat-sink cooling;
• Less moving weight to reduce vibration and ghosting;
• Professional SLS 3D printed housing and 3 other key parts.

This Upgrade Kit is mostly similar to the previous MK3S, with the main difference of having been designed to fit the Mosquito and Mosquito Magnum hotends.
Other differences come from the design changes that include:

• An optimization of the cooling air channel to focus the airflow on the Mosquito’s heatsink. The channel is narrower.
• This tighter space is also used to hold the hotend in place during nozzle changes, so the user can change the nozzle with a single hand.
• The fan shroud was also redesigned to fit the Mosquito hotends.
• We include in this kit a new part, the Mosquito hotend adapter, 3D printed with SLS.

The Upgrade is compatible with the thermistor and 40w heater already supplied with the Prusa.
However, you also have the option of using the more efficient Mosquito thermistor and 50W heater.
We especially recommend this option to use with a Mosquito Magnum.

• If you have a Prusa i3 MK2.5S, buy the 12v Mosquito heater.
• If you have a Prusa i3 MK3S, you should buy the 24v Mosquito heater.

To use this upgrade in the MK2.5S / MK3S, the E-steps and Z_Max needs to be updated. Check out the latest version of our firmware here.
We are also supplying firmware versions compatible with the use of Mosquito’s thermistor.
If you are using this Mosquito’s component you should use the related firmware.

This is a co-development work with awesome guys in the Prusa Community like Chris Warkocki, Grégorie Saunier (Bear Upgrades), Olof Ogland, Erik Bjorgan, Josh Jones, Kyle Wiehe, Marc Evertz, Matt Harrison, Ocie Ward, Sando Bendig, Vecko Kojchevski (Vecko Extruder), Steven Mölby, and Yuri Delia that have provided excellent feedback and suggestions of how to develop the ”perfect” extruder setup for the Prusa series printer. A lot of work has been put in this project and we tried to listen to all the inputs in order to find a solution that can be the best fit to the Prusa I3 MK3S.