Black Friday: lifetime access is on a special offer in the app, until November 30. Black Friday: special offer on lifetime access, until November 30. Download
이 감폭계는 소리의 강도를 측정하는 데 사용됩니다.I gampokgyeun soriui gangdoreul cheugjeonghaneun de sayongdoemnida.This decremeter is used to measure the intensity of sound.