The Nady WHT-15 TX is a wireless handheld microphone transmitter that works with the following receivers (receiver not included): Nady Encore I and II and Duet series receivers Nady 101, 401 and 401X QUAD receivers Nady DKW series receivers Nady WA 120 series receivers Nady 151 and 351 VR camcorder series receivers Other Nady receivers using the same frequency The microphone operates on one 9 volt battery (not included) that is neatly concealed in the base of the microphone. The microphone has a rubberized non-slip covering and a wire mesh screen. Also includes an integrated on/off switch with a power-on LED indicator. Dimensions: 9.25" x 1.875" x 1.875"; Weight: 6.25 ounces (without battery). NOTE! The WHT microphone transmitters are frequency specific, and must match the exact frequency of your Nady receiver or the microphone transmitter you are replacing. Check the back of your receiver or the bottom of the microphone transmitter to find the correct frequency before ordering. Please call before ordering if you need assistance.