Upgrades & compatible parts for the Prusa MK4 / MK4S
The Prusa MK4 / MK4S (Prusa, 2023) has a 250×210 mm bed, direct drive and a bedslinger design. Those specs decide what fits. Here's the matching upgrade and spare-parts list — free printable mods and buyable parts.
PEI spring-steel build plate
Look for a 250×210 mm spring-steel plate — that exact size is what fits.
Nozzles (brass / hardened)
MK4 uses the Nextruder with its own nozzle format — get Prusa/Nextruder nozzles (CHT/hardened available).
Hotend / high-flow upgrade
All-metal or high-flow (CHT/Volcano) hotends boost speed and let you print high temps — popular on this printer.
Extruder & drive gears
Already a direct-drive extruder — upgrades are mostly hardened drive gears or a dual-gear conversion.
Part-cooling fan duct
Enclosure
An enclosure keeps ABS/ASA warp-free and cuts noise — ready-made tents and printed panels both work.
Spool holder
Tons of printer-specific holders exist — from simple arms to bearing-mounted spinners.
Filament runout sensor
Many newer models already include a runout sensor — check yours before adding one.
Belt tensioner
A printed X/Y belt tensioner removes belt slack and tightens up your dimensions — cheap, high impact.
Cable chain / management
Tidy the wiring and protect it from snags — a satisfying first print upgrade.
Filament (PLA / PETG)
The one thing you'll buy again and again — match diameter (1.75 mm) and dial temps to the brand.
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