Abstract: A protective material for surrounding the inside of an infant's crib includes at least one panel having a substantial rectangular shape. The panel is composed of felt and has a plurality of apertures formed completely through the panel. The apertures comprise between 25% and 60% of the surface area of the panel. The panel has sufficient rigidity so that when positioned upright, and held from a bottom edge, the panel remains in the upright position. At least one fastener secures the panel to the side of a crib. In various further forms, the protective material may comprise a single panel having four segments which are foldably attached to one another, folded inward 90 degrees to thereby form four sides of a substantially rectangular box. Alternatively, the bumper comprises four discrete, separate panels.