Sennheiser is offering custom-fit ear tips to refine the sound of its wired earbuds | TechRadar
KZ ZSN PRO X Wired Earbuds,in-Ear Headphones with Dual Driver-Clear Sound and Ergonomic Custom-Fit Earpieces (S/M/L),Bass Ear Buds,3.5mm Jack for Phones,Computer and Laptops (Black Without Mic): Amazon.co.uk: Electronics & Photo
The quest to find the perfect pair of earphones: Are custom, 3D printed earbuds the solution? | The Independent | The Independent
Custom fit earphones: Audio nirvana or a waste of money? | Ars Technica
Snugs custom fit earphones review | Stuff
Custom fit earphones: Audio nirvana or a waste of money? | Ars Technica