CMT Magnetic Buzzer Transducers CUI Devices CMT Magnetic Buzzer Transducers offer sound pressure levels (SPL) that range from 75dB to 97dB. These devices feature an 800Hz to 4000Hz typical frequency range and -30°C to +85°C operating temperature range. These externally driven audio transducers are available in both surface-mount and through-hole mounting styles. CUI Devices CMT Magnetic Buzzer Transducers are ideal for a variety of consumer electronics, industrial, and portable equipment applications.