The Dosy FC50 6-Digit Inline Frequency Counter is a high-quality tool used for measuring the frequency of a power supply. With a sleek design and accurate readings, this frequency counter is perfect for various CB and ham radio applications. Dosy is a trusted brand known for producing reliable measurement instruments. For 12V radios (CB, 10 meter, 12 meter, etc.) Accurately measures frequency from .5 MHz to 50 MHz Has Input/Output Type SO-239 connectors 500 Watts Max External Input Sensitivity: 0.1 - 1V MAX RF Signal: Direct Reading Internal Input R T / X Frequency: 10.695MHz Built-in adder Power Supply: DC 13.8V 5% Negative Ground (not included) Blue LED Display Dosy Professional Architecture