Slipstick CB840 3-1/4″ Bed Roller / Furniture Wheel Gripper Cups (set of 4) Caramel Color Price:  $9.99 (as of 18/10/2017 13:11 PST- Details)

Unique cup design locks furniture or bed wheels in place while protecting floors from damage
Caster cups are ideal for 2″ diameter (50 mm) wheels up to 2-1/4″ wide
Patented rubber O-ring bottom keeps floors perfect by preventing unwanted movement