To borrow from film terminology, this model is like a Technicolor, 70 mm Panavision version of the U3 model, with a vividly colorful tone, an barrel-chested bass, a huge dynamic range, and a perfectly weighted and super-responsive keyboard. It is also one of Yamaha’s famous “X” models with a radial back post design. Ideal for the advanced pianist or student. In short, this piano was designed for the demanding professional pianist or teacher who wants a grand but needs an upright. Potent stuff!!