Available in clear, black or brown lucite and a variety of wood finishes, caster cups are a beautiful way to protect your carpet or floor from the weight (up to 1200 lbs) of a grand piano. Caster cups also play an important role in prolonging your grand piano's life. When you play, your piano vibrates both from the resonance of the strings and from the impact of your fingers. Placing your piano on caster cups reduces the stresses on your piano's leg joints by allowing the piano to move slightly with these vibrations. It's a great way to protect both your instrument and your floor.