รายละเอียดสินค้า : 

• HD 2020 sound level calibrator 
• portable, battery operated sound source 
• suitable for sound level meters (portable and laboratory) and acoustic stations 
• class 1 according to IEC60942:2003 with LCD display. 
• ISO 9001 calibration report included. 
• 1000Hz frequency allows calibrating sound level meters with any weighting