What parts are suitable replacements for an Ender 3 Pro?
The Ender 3 takes an M6 thread (metric 6&nbsp;mm diameter). Measurement of stock nozzle shown. 

Most sellers will list compatible printers Ender 2, Ender 3, Ender 4, CR-10, CR-10S, CR-10 Mini, CR-10-S4, CR-10-S5, CR-8, CR-7. Will Also Fit Any Other MK10 Heater Blocks. 

I recently bought some titanium alloy nozzles as the brass one got closed over after crashing into the glass bed.