http://www.superlux.com.tw/upload/function.product.info/11755a60-22ef-45f1-9e49-ccaa6598a5a2/resource/br_HD381_Series_web_en.pdf
http://www.superlux.com.tw/upload/function.product.info/11755a60-22ef-45f1-9e49-ccaa6598a5a2/resource/br_HD381_Series_web_en.pdf