0 or QC3. ) batteries die. Initial impressions were a huge amount of detail, more so than the SE535. Very good comfort and sound quality I was used over the time with earphones cables and when I bought these I was like. ) So i bought these. I think the price point is just right and makes it a solid bargain. They look cool, but always same story: Without any apparent reason, from one day to another, they stop working properly and instead put out tinny, clanking, and weak sound. These are very comfy slippers but I do not understand the reviews that say they run small. The white bottom makes it a cut above the rest.