Etymotic Research ID:hqrMgB+s

ER4　えーあーる
http://ko.goldenears.net/board/?mid=UR_Earphones&search_target=title&search_keyword=er4&document_srl=4978006

https://www.googledrive.com/host/0BwoiaHGVACz6LUtSRjhEckNiV1E