If you make crystal radios, you’ve probably got a few crystal earpieces. The name similarity is a bit coincidental. The crystal in a crystal radio was a rectifier (most often, these days ...

Acoustic tube and Medium Earmold easy to be Replaced and operated; Replacement Acoustic tube: Covert acoustic air tube transmits more clear sound and protect the eardrum from sound wave ...

This led to many discussions, and the UCI also implemented changes such as tests with earpieces and yellow cards. Lappartient shared his thoughts on the outcome of these actions. Text continues ...