So these are the Sony WH-CH520’s, they came out along side the Sony WH-CH720N, and after checking out the WH-CH720N’s I decided that I needed to checkout the WH-CH520’s, just cause I saw so many improvements on the WH-CH720N’s. And to be honest, I was not disappointed, cause just like the WH-CH720N’s, the WH-CH520’s have also gotten some important improvements from its predecessors.