From the manufacturer's website: "Our first flagship product, ITSFIT R3 is the result of 2 years of relentless efforts in order to create a true, satisfying and customizable Reference in-ear monitor. Every pair of R3 goes with such delicate handcrafted shells that please you from the first try...

Driver Unit Balanced amature Frequency Response 20 Hz – 20.000 Hz Sensitivity 110 dB/mW Nominal Impedance 47 Ohms Weight ~16 g (without cable) Transducer principle Universal fit Socket 2 pins – 0.78 mm Country of Manufacture Vietnam

Design: 3 Way Crossover Drivers: 3 BA driver/ side Freq. Range: 16-17000Hz Impedance: 26Ω Cable connector: 2 pin 0.78mm Made in: Vietnam

Head-fi thread: https://www.head-fi.org/threads/burson-audio-fun-2w-pc-class-a-headphone-amp.881515/

Designed and manufactured in Vietnam. Image by Ying Phan (AYA's founder).

Costing (around $300), the AT10 has been developed over the course of 3 years by Notes Audio. The result was a pair of dynamic IEMs that offer a warm, unique sound in a reasonably priced package.