Small staff that may work wonders (4)
I believe the answer is:
wand
'small staff' is the definition.
'wand' can be an answer for 'staff' (I have seen 'Magical staff ' mean 'wand' so perhaps 'staff' could also mean 'wand'). I am unsure of the 'small' bit.
'may work wonders' is the wordplay.
I cannot quite see how this works, but
'work' could be 'w' (physics abbreviation) and 'w' is found within the answer.
The remaining letters 'and' is a valid word which might be clued in a way I don't see.
This explanation may well be incorrect...
'that' is the link.
Can you help me to learn more?
(Other definitions for wand that I've seen before include "Extremely angry" , "Magic baton" , "Conjuror's stick" , "Rod of magician or water-diviner" , "Magician's accessory" .)