This has to be the best upgrade so far. Fits perfectly. Heats up faster than the nozzle. 80C in just a few minutes. The only down side is that with the external box when the print finishes it doesn't turn off the bed heater. Trying to fix that with some TP Link plugs. One note though it makes your bed sit higher so had to build an adjustment for my Z axis switch. Basically ended up moving the Z axis limit switch up about 5 mm.Yes it does take a lot of time to get in but once you do and get your printer redialed in you won't regret it. It vastly decreases by print time by virtually wiping out the bed heating time. I can turn on the printer and bed heater and go send a print to octopi and by the time the nozzle gets up to temp the bed is ready to go (saves about 40 minute compare to the old way).Note that while you should unsolder the old bed heater you still need to leave it connected if you don't reflash the firmware so that the temp senor at least gets some reading. Otherwise if you remove it you can't print due to bed min temp warnings. Personally I rehooked the wiring up and heat shrunk each bed heater wire so they can't possibly touch anything. The temp sensor always reads 18C. Unchecked heated bed in both Cura and Octopi.The only down side was the wait for it to arrive. Took one afternoon to install. Mostly due to cleaning old glue and insulation off original bed.