Model 708A deluxe base microphone. TEN-TEC model 708A is an omnidirectional dynamic microphone designed for use as a communications station microphone for Amateur Radio and other transmitting applications. The unit consists of a metal die-cast base (plastic bottom cover) with 3 position PTT switch with momentary TX, OFF, and LOCK positions, flexible metal gooseneck, dynamic microphone element and ball-type element housing. The element has a tailored frequency response from 30 Hz to 12 kHz designed for excellent transmit audio in SSB, AM, and FM modes.