REED R8090 Offers
This sound calibrator generates a stable acoustic signal at a controlled frequency and amplitude to verify the accuracy of your sound level meter. The R8090 is compatible with all 1/2 diameter microphones.

Features
Generates stable acoustic signal at a controlled frequency and amplitude to verify sound level meter accuracy
Accommodates sound meters with 1/2 diameter microphones
Simply place calibrator on microphone, turn on and adjust your sound level meter
Complies with IEC 942 Class 2