Best isolation. But spiral ear hand-makes every single mould of SE5, no scanning, no dipping into acrylic melt. My ears are small, but thankfully Grzegorz tried his best to fit a se5 in them, but I have such a weird right ear shape that even the silicone SE5 makes it sore after 1-2 hours.
I only had the soreness on my right ear for 2 weeks after getting my first custom. After that I don't feel anything while it's in my ears. Downside is now people are telling me I'm a snob coz I sometimes forgot they are still in my ear and can hear everyone around talking. lol