Printer model
Original Prusa MK3S+: V6 nozzles and the MK4S upgrade kit
Prusa's MK3S+ facts: V6-type nozzles, its 280 °C and 2.5 N·m nozzle change, the PSU assembly that fits it, and what the MK4S upgrade kit reuses.
Also listed as MK3S, MK3
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Short answer
The MK3S+ takes E3D V6-type nozzles; Prusa changes them at 280 °C and its service team tightens to 2.5 N·m. Prusa's MK3/S/+ to MK4S kit reuses the frame, PSU, MK52 heatbed and X/Y rods and bearings, and adds an xBuddy board, Nextruder, motors and a CHT nozzle. A 2+1-screw bed or a silver PSU changes what you order.
What fitsAll 3 items that fit
- Wear-resistant V6 nozzleMicro Swiss CM2 RepRap (V6) 1.75 mm nozzle (M2902)Check price on Amazon
- Hardened steel V6 nozzleMicro Swiss M2 hardened high speed steel RepRap (V6) 1.75 mm nozzle, 0.4 mm (M2600‑04)Check price on Amazon
Key facts
- Build volume
- Not confirmed
- Motion system
- Not confirmed
- Stock extruder
- Not confirmed
- Stock hotend
- Not confirmed
- Nozzle standard
- E3D V6-type nozzles[1][2]Prusa says any V6-compatible nozzle can be fitted, except the Olsson Ruby, which follows its maker's instructions.
- Stock nozzle
- 0.4 mm brass V6[2]
- Max nozzle temperature
- Not confirmed
- Max bed temperature
- Not confirmed
- Firmware
- Not confirmed
- Latest listed firmware
- Not confirmed
- Power input
- Prusa's PSU 24V 240W assembly is listed for the MK3/S/+ (24 V, 240 W, 10 A max)[3]Prusa's page states no input range. The same assembly is not compatible with the MK4, XL or CORE One. Replacing a power supply is mains work: follow Prusa's guide or use a qualified technician.
- Hardware revisions
- Heatbed screw pattern (2+1 or 2+3) and PSU color (silver or black) decide the MK4S kit options[4]A 2+1-screw heatbed must be replaced; a 2+3-screw bed is compatible. A black PSU works as is; a silver PSU needs a harness, adapter or black PSU. Early MK3s may lack a spool holder.
- Maker maintenance rules
- Nozzle change: heat to 280 °C; Prusa's service team tightens to 2.5 N·m[2]Prusa's guide for the MK2.5/S, MK3/S/+ and MK3.5/S. Do not apply it to Nextruder printers.
- Documented upgrade kits
- Prusa MK3/S/+ to MK4S kit: reuses the frame, PSU, MK52 heatbed and X/Y rods and bearings; adds an xBuddy board, Nextruder, motors and a 0.4 mm CHT nozzle[4]A self-assembly kit. Buyers select PSU and heatbed options when ordering.
- Recall status
- No recall found on 2026-10-08[5]On 2026-10-08 we found the Bambu Lab A1 recall as the only 3D printer recall in CPSC's notices. That is a dated search, not proof that no recall exists.
- Not confirmed
- Not confirmedOur MK3S+ sources were Prusa's nozzle, PSU and upgrade-kit pages.
Watch out for
- Check your heatbed screws and PSU color before ordering the MK4S kit: a 2+1-screw bed must be replaced and a silver PSU needs a harness, adapter or black PSU.
- The MK4S kit is a self-assembly conversion, not a set of parts to swap between an MK3S+ and an MK4S.
- Prusa lists the MK3S and MK3S+ among printers not compatible with its official Accelerometer Set.
- The Olsson Ruby is the exception to Prusa's V6 nozzle procedure; follow its maker's instructions.
What fits
Product details below are the seller's own description unless a source is shown. Pick the variant named for each item.
V6 brass nozzle
E3D V6 brass nozzle, 1.75 mm x 0.40 mm (V6‑NOZZLE‑175‑400)Choose the 1.75 mm x 0.40 mm brass V6 nozzle (V6-NOZZLE-175-400).
E3D says its V6 brass nozzles are fully compatible with Prusa printers, and Prusa groups the MK3S+ with the V6-type nozzle printers. Tighten V6 nozzles hot, as Prusa says.
Wear-resistant V6 nozzle
Micro Swiss CM2 RepRap (V6) 1.75 mm nozzle (M2902)Choose the 0.4 mm CM2 RepRap nozzle (M2902-04).
Micro Swiss lists the Prusa i3 MK3, not the MK3S+ by name; Prusa groups the MK3/S/+ as V6-type nozzle printers.
Hardened steel V6 nozzle
Micro Swiss M2 hardened high speed steel RepRap (V6) 1.75 mm nozzle, 0.4 mm (M2600‑04)Choose the 0.4 mm M2 RepRap nozzle (M2600-04).
Micro Swiss lists the Prusa i3 MK3, not the MK3S+ by name; Prusa groups the MK3/S/+ as V6-type nozzle printers.
Aliases: Prusa groups the MK3, MK3S and MK3S+ as V6-type nozzle printers, and its nozzle-change guide and PSU page name the MK3/S/+ together. The MK4S kit options above depend on how your MK3 was built.
Questions
What does the MK3S+ to MK4S kit reuse?
Prusa says it reuses the original frame, PSU, MK52 heatbed and X/Y rods and bearings, and supplies a new xBuddy board, Nextruder, motors and a 0.4 mm CHT nozzle. See MK3S+ and MK4 to MK4S upgrades.[4]
How tight should an MK3S+ nozzle be?
Prusa's guide heats the nozzle to 280 °C, and its service team uses 2.5 N·m. That figure is Prusa's, for its V6 printers.[2]
Does my MK3S+ work with the MK4S kit as is?
It depends on the build. Prusa says a heatbed with 2+1 screws must be replaced, while a 2+3-screw bed is compatible, and a silver PSU needs a harness, adapter or black PSU.[4]