Assertion: tripod's ball head | /r/HasAspect | one or more cutouts
Facets:
value: for 90 degrees
type: OTHER
value: in the housing
type: LOCATION
Source sentences:
text: For positioning the camera 90 degrees from horizontal, many ball heads have one or more cutouts in the housing that allow the ball’s stem to swivel down and be positioned at right angles to vertical.