Mallet indication
This is the mallet indication. It usually indicates only the hardness of the mallet, omitting the mallet type (whichever is idiomatic for the instrument).
Where there could be ambiguity, the mallet is given a full description. If none is indicated, it may mean the previously used mallet is still in use, even if it belongs to a different instrument.
Only for the following instruments:Keyboard percussionMarimbaPercussionVibraphone