Cheap And Discounts 30dB~130dB Onboard Noise Sensor Module TTL/RS485 Industrial Grade Sound Sensor 4.5V~5.5V/10~28V Noise Generator Decibel Tester Wholesale. Buy Directly From Merchant Newswan Tool & Instrument 04 Store. Enjoy ✓Free Shipping Worldwide! ✓90 Days Buyer Protection. ✓Easy Return. ✓Money Back Guarantee.