Prusa Research · Bed slinger · 2023
Prusa MK4
The MK4 shipped in March 2023 and was the biggest change to the Prusa i3 in years. The Nextruder replaced the old Bondtech extruder with a 10:1 planetary gearbox, an all-metal filament path and nozzles you can swap in a minute. A load cell in the toolhead now felt the bed directly, which ended the Live Adjust Z ritual MK3 owners knew well. It also brought 32-bit xBuddy electronics, input shaping, pressure advance, and Ethernet with a Wi-Fi module in the box. The magnetic bed didn't change, so old MK3 sheets fit. The MK4S replaced it in August 2024, and Prusa sells an official kit that upgrades an MK4 to one, so a used MK4 has somewhere to go.
MK4 assembledMK4 kitMK4 with MMU3MK4 with the MK4S upgrade kit fitted
Spec at a glance
- Maker
- Prusa Research
- Type
- FDM, Bed slinger
- Launched
- 2023
- Build volume
- 250 x 210 x 220 mm
- Extruder
- Nextruder direct drive, 10:1 planetary gearbox, all-metal path
- Max temperatures
- Nozzle 300 °C at launch, bed 120 °C
- Bed
- Magnetic heatbed, PEI spring-steel sheets (MK3 sheets fit)
- Levelling
- Load cell
- Connectivity
- Ethernet, Wi-Fi module included, PrusaLink
- Also listed as
- Original Prusa MK4, MK4
- Typical eBay ask (Oct 19, 2026)
- $790–$790
Printer check
Hours, hotend, bed and firmware
- Print hours
- Like every Buddy-firmware Prusa, it shows total print time under LCD Menu, Info, Print Statistics. Get a picture of it, and remember a full factory reset clears it.
- Hotend and nozzle
- The Nextruder has a 10:1 planetary gearbox, an all-metal filament path and quick-swap nozzles, with 0.4 mm as standard. Ask for a close photo of the nozzle tip and whether spare nozzles come with it.
- Bed and levelling
- A load cell in the Nextruder feels the bed, so there's no Live Adjust Z to set. The magnetic heatbed takes the same PEI spring-steel sheets as the MK3 series. Check the sheet in the photos for bald patches.
- Belts, rails and screws
- It's a bed slinger with input shaping and pressure advance. Have the seller twang the X and Y belts and slide the bed. Both belts should feel tight, and the bed shouldn't catch.
- Firmware and account
- The firmware is open source and shared with the XL and MINI+. Prusa sells an official MK4 to MK4S upgrade kit. On firmware 6.4.0 or later, the Ownership transfer reset clears the seller's network and Prusa Connect settings but keeps the statistics, so ask for that before shipping.
- Enclosure and add-ons
- It takes the MMU3 multi-material unit. Check the listing for an MMU3 or the MK4S upgrade kit, and whether the kit is fitted or still boxed.
- Spare parts
- Prusa's shop sells MK4 spare parts, including a spare parts bundle for the MK4, nozzles and the filament guide set. Parts are easy to get.
- Shipping and packaging
- The MK4 travels with its extruder padded and zip-tied in place, the way Prusa's packing guide shows. Ask whether the original box and packing are still around.
Should come with it
- A PEI spring-steel sheet
- The Wi-Fi module
- Power cable and spool holder
Check the listing photos against these lists, and ask the seller about anything you can’t see. A missing sheet, add-on or power supply should come off the price.
What to check
Prusa lists no known MK4 fault. Judge it on the nozzle, the sheet, the belts and a recent print.
- 01Print statistics: Ask for a photo of LCD Menu, Info, Print Statistics. It shows total print time and failed prints.
- 02MK4 or MK4S: Ask whether the MK4S upgrade kit is fitted. A converted printer should show the new cooling and run MK4S firmware.
- 03Recent print: Ask for a photo of a recent print with the first layer up. Even lines mean the load cell is working.
- 04Nozzle: Ask for a close photo of the nozzle tip. Clean and round is good.
- 05Sheet: Look at the sheet in the photos. An even surface is good, and bald patches mean a new sheet.
- 06Belts: Ask the seller to pluck the X and Y belts. They should feel taut and twang.
- 07Ownership transfer: Ask the seller to run the Ownership transfer reset before shipping. It clears their network settings and keeps the statistics.
New to used printers? How to check a used 3D printer covers hours, nozzles, beds, belts and shipping damage, and accounts, firmware and cloud binding covers what the seller should sort out before it ships.
Buying guide
Which one to buy
§ Oct 19, 2026Only one MK4 is for sale, and it's an MK3 upgraded to an MK4, with an enclosure and web camera, at $787 delivered. A converted printer is a fair buy if the conversion is complete, so ask for a close photo of the Nextruder on the toolhead and of LCD Menu, Info, Print Statistics. Ask for the Ownership transfer reset, and for the extruder padded and tied down the way Prusa's packing guide shows.
- Listed now
- 1
- For parts
- 0
- Typical ask
- $790–$790
- Full range
- $750–$750
Snapshot
For sale on eBay
1 of 1 listedChecked . Some may have sold.
Delivered prices include shipping as eBay quoted it to a US address on Oct 19, 2026. Many sellers charge by distance, so your total may differ. eBay shows yours before you pay.
UsedUpgraded Prusa MK3 to MK4 3D Printer Assembled with Enclosure and Web Camera
$786.81est. delivered
$750.00 + $36.81 shipping
Buy It Now$750.00
Offers accepted
This seller takes offers, and many sellers accept less than the asking price.
Fine if you might miss it? Send an offer first. Someone else can still buy it while you wait for a reply.
Want it for sure? Use Buy It Now.
Our take
MK3 converted to MK4, with an enclosure and web camera.
Seller: fxmaster123456789
100% positive
Prices change daily. The live eBay search shows everything listed now, including anything new since Oct 19, 2026.
See every listing on eBay ↗eBay searchCompare with
Prusa Research
FDMPrusa MK4S
- Build volume
- 250 x 210 x 220 mm
- Launched
- 2024
- Type
- Bed slinger · Multi-material
$850–$1,375 typical ask
Prusa Research
FDMPrusa MK3S+
- Build volume
- 250 x 210 x 210 mm
- Launched
- 2020
- Type
- Bed slinger · Multi-material
$420–$525 typical ask
Bambu Lab
FDMBambu Lab P1S
- Build volume
- 256 x 256 x 256 mm
- Launched
- 2023
- Type
- CoreXY · Enclosed · Multi-material
$330–$390 typical ask
Bambu Lab
FDMBambu Lab A1
- Build volume
- 256 x 256 x 256 mm
- Launched
- 2023
- Type
- Bed slinger · Multi-material
$280–$410 typical ask