A.250~1000Hz氣導(dǎo)聽力改善≥5dB B.250~1000Hz氣導(dǎo)聽力改善≥10dB C.250~1000Hz氣導(dǎo)聽力改善≥15dB D.250~1000Hz氣導(dǎo)聽力改善≥20dB E.250~1000Hz氣導(dǎo)聽力改善≥25dB
A.泄水閥B.減壓閥C.安全水封D.放氣閥