Tools for accessing features on a piano (4)
I believe the answer is:
keys
This clue is a double definition.
'tools for accessing' is the first definition.
(keys are used to access things)
'features on a piano' is the second definition.
(pianos have keys)
(Other definitions for keys that I've seen before include "Landing places" , "Lock-openers?" , "Low islands, sycamore fruits" , "Lockers" , "Bunch of openers?" .)