The Shure SRH240A closed-back headphones are a comfortable update to the original design, but with the same great sound and durability. While right at home in the studio, the SRH240As are optimized for the impedance and signal levels of consumer devices like MP3 players, laptops and the like. Their sound is clear and hi-fi with minimal distortion, and ear fatigue is kept to a minimum even through long listening sessions. When you're listening on a loud train for your morning commute, the SRH240As will come to the rescue with their great isolation from surrounding noises.