Prus i3 Hotend MK3S+ J-Head Extruder Kit 24V 40W for 1.75mm Direct Filament Compatible with Prus i3 MK3/MK3S/MK3S+ and Other E3 V6 Remote Printhead Printer with Silicon Cover and 0.4mm Nozzle

Works great, good heating and fit my printer exactly.

I bought this hotend to replace the stock hotend in my Prusa MK3S+ after a heating element wire broke. After reading other reviews, I was worried that the heatsink would not fit, or that the cable connectors wouldn't match. Fortunately this proved to be a non-issue; I had the hotend installed within 30 minutes with no issues. After running PID calibration, thermal calibration, and adjusting Z-height, I was producing great-looking PETG prints that would have been challenging with the stock hotend. The silicone sock is a great addition, keeping the hotend cleaner and better insulated. I'd absolutely recommend this hotend and might purchase a second as a backup.

This has been of a letdown. The silicon sock provided doesn't fit properly or otherwise comes loose and the thermistor does not fit the heat block correctly. It can't be locked down by the bolt that closes the gap in the heatblock. This means the silicon sock can pull the thermistor out of the heat block, killing a job and creating a thermal anomaly. Fitting it was easy. The PTFE tube needed to be trimmed to fit. Seems like it could be sized more accurately but I'd rather have too much than too little. This is a repeat purchase, initially as a spare, but the previous one had to be replaced when it jammed which makes me wonder if this one is going to have the same problem. All in all, decent value but maybe not as much peace of mind as I would like. Not convinced I'll order another as a replacement. EDIT: I have to knock this down to 1 star as it failed on me about months after buying it. It jammed in such a way I had to throw the whole thing out, with the cables. I could salvage nothing. Looking back at my orders, this isn't the first time. I don't think hot-ends are supposed to be consumables.

It’s too early to tell how long this will last considering I have not even finished printing the first part yet but so far it is extruding prusa pteg filament really well. I initially had the original prusa hotend on order but the shipping date kept pushing out even a week after my purchase so I couldn’t wait any longer and took the leap of faith with this brand. If this holds well I will be a repeat customer. Update: Printed several other parts out of PETG without issues. This hotend rocks!

I upgraded my MK3.5S to an E3D Revo nozzle and it wasn't working properly so I bought this to go back to stock (I lost the original hotend). Perfect stock replacement. Passes all Prusa xbuddy tests.

My hot end heater cartridge wires broke, as many do over time. Prusa is out of stock and doesn’t seem to be offering replacements. I didn’t want to deal with upgrading to a different hot end and firmware since I use an MMU. After some research, this hot end seemed like a close OEM replacement with a possible slight upgrade—and I was right. It includes a hot end cover to prevent filament from burning on the hot end, a new PTFE tube, and a copper throat. It was a direct replacement with no modifications needed and even seems more durable than the OEM part.

I wanted to replace the heatsink, but it has two major issues that will waste your time and money. 1) The plastic fitting at the top will not fit into the Prusa Extruder body - it's almost 1mm bigger than the housing. Even if you cut it - you will face the next issue. 2) The outer diameter of the heatsink is 0.3 mm less than it should be! It will sit lose in the housing and give you bad print quality.

As part of the process of evolving a i3 clone (as in, the Mk1) into a "real" Prusa (something adjacent to the Mk3S), I recently bought this J-head as the e3d v6 clones I had on hand would not fit into Prusa's R7 Mk3S extruder geometry, those using screwed-in PC4 couplings instead. While I've bothered to get some of the hardware from Prusa directly, doing this for all parts would get too expensive too fast, so I chose to source the hotend (along with some other components) from Fysetc. The Fysetc J-head came fully assembled (minus PTFE Guide, which you trim and insert yourself) and even apparently heat tightened, which was a pleasant surprise- I am used to v6 clones usually only being hand tightened, if tightened or even assembled at all. This made the process of assembling the extruder similar to assembling the official extruder out of the official kit; simply cut the PTFE guide to length, insert it into the hotend, then put the hotend into the extruder back, align cables and place the front parts of the assembly onto it and tighten. A thing I will note is that the PTFE tube it came with fits and allows filament through, but seems to have a very tight inner diameter and seems stiff for PTFE. I'm sure it'd work fine, but I however used some of my own PTFE with a 1.8mm inner diameter instead. In terms of function it's still early days, but while I have issues with other parts of the older hardware, this hotend and the extruder as a whole has functioned very well. Even running with a 12v heater cartridge (the machine has yet to be converted to 24v as I do not yet have the 24v hotbed) it reaches (and overshoots) temp quickly (2-3 minutes or less from 17 C to 215 C). This causes a noticeable amount of oozing and stringing when printing with PLA, and possibly a bit of over-extrusion, but in my experience this is to be expected with all-metal hotends, so dropping print temps 10 degrees on the hotend is recommended. I would also advise others using the hotend to run some PID tuning as well. Generally, the oozing has not been a problem for me (I have larger problems like a bent leadscrew and sensorless homing sometimes acting weird) other than top surfaces looking a over extruded, but this can probably be fixed with further tuning of the printer and print settings. All in all, while I was prepared to get something similar to the usual cheap v6 clones, this was a pleasant surprise, and a good value.

On right is original prusa left is what it came as. Got ripped off.

This does not fit the MK3S+ as advertised, as shown in the picture the ends are different.