Supporting up to 40 lbs. per bumper or 160 lbs. per four bumpers, the 3M Bumpon Easy Slide Protective Products SJ-6344 take the hassle out of sliding computers, monitors and other pieces of office equipment around on the desktop. The round, black bumpers are made of polyurethane and feature a durable, high-performance synthetic rubber adhesive that provides excellent initial and permanent adhesion to a wide variety of substrates, including many low-surface energy surfaces. The non-marring, non-staining bumpers offer cushioning and surface protection, will not crack, and have passed UL94HB flammability requirements.