Caster Cups for Furniture Legs fit on the base of tables and chair legs, adding eye catching appeal to furniture. These functional nickel or solid brass caster cups strengthen and protect ends of furniture legs from daily wear and tear. Square and round caster cups have been used to define many styles and periods of furniture. Over time the name has evolved from ferrules or sabots to leg cups. Available in brass, antique brass and nickel. Choose finish to best match your decor. Offered in square and round shapes. Choose from three commonly used sizes.