Drywall / Sheetrock Anchors
Hollow wall anchors are used to mount fixtures to drywall (a.k.a., sheetrock and gypsum wallboard). Hollow wall anchors can be used for cinder block applications.
The purpose of the hollow wall anchor is to provide a mushroomed head inside the hollow wall. Without the mushroom head, the anchor would lose its grip and slip causing the fixture to fall to the ground.