Which adapter am I missing for my washing mashine?
Unscrew the spigot from the tap and then the washing machine pipe will screw straight on to the 3/4 thread.
Edit based on comments:
This is a picture of a &quot;normal&quot; standard replacement hose. Do note both ends have plastic fittings which are standard. there are stainless wrapped versions but they are only rated to the same working pressure anyway.
Used these many times and the only time I ever saw one of the plastic nuts break was when it had a gorilla crush it with mole-grips, hand tight is more than ample.

Edit 2:
To help those who have not seen the pipe style with the electric valve, here is a picture: