Custom fit earphones: Audio nirvana or a waste of money? | Ars Technica
Collin's Lab: Custom Fit Earbuds - YouTube
Campfire Audio Equinox - Single Driver Custom IEM Earphones
ZenPlugs Custom Moulded In-Ear Monitors
Custom in-ear headphones are the supercars of personal audio - The Verge
Panasonic ErgoFit Wired Earbuds, In-Ear Headphones with Dynamic Crystal-Clear Sound and Ergonomic Custom-Fit Earpieces (S/M/L), 3.5mm Jack for Phones and Laptops, No Mic - RP-HJE120-A (Blue) : Amazon.co.uk: Electronics & Photo