The QRS Piano Player System Processor, Part # 20-1581C, is a specialized unit designed for playing piano music using a piano roll. Made by the brand QRS, known for its quality products in the musical instruments industry, this processor is specifically designed for pianos and offers a convenient and automated way to play piano music. The model number 20-1581C indicates a specific design that is likely compatible with a range of pianos, making it a versatile option for musicians and music enthusiasts looking to enhance their piano playing experience.