I couldn’t find any info on the driver size of the ER2 series so I contacted Etymotic and got an official number from them.
The official response I got from them is that the driver size of the ER2 series is 5.8mm.
Month: September 2020
Koss KPH30i – Unboxing
Unboxing the Koss KPH30i. Feel free to leave a comment if you have any questions.