I needed something with a ton of isolation for music and navigation on a motorcycle. I used to have some HF5s that I used until the cable frayed at the jack. I ended up getting CIEMs and used them for two years but wasn't ever happy with them. When Ety released the ER3, I was excited to try them out and MD had a drop just in time. I like some extra zing in the bass and sub bass region, so I went with the XR. They're great- everything I loved about the HF5 with some extra clarity and a little bass boost. Crazy good isolation and sound quality, a removable cable, and a price well below the pro model. They even scale well. Highly recommend these!