Assertion: accordion's key | /r/AtLocation | their upward limit
Facets:
Source sentences:
text: The next steps are to select the right combination of materials to use as white key stops to limit their downward travel to exactly the distance you selected early on, and to select the correct materials to use as black key stops to prevent the black keys from submerging below the level of the white keys when the white keys are at rest at their upward limit (you don't want excessive black key travel to cause you to inadvertently depress a white key while playing).