An improved detachable conference telephone and particularly a structure allowing microphone seats to detach and separate from the conference telephone main body. In one embodiment, one subassembly includes a motor located within a cased section of the borehole that rotates a drill pipe segment attached to a rotary drill bit in the open-hole to drill the open-hole extension of the well. This way the seat is flushed with cleaning liquid and is thereby cleaned. A first pixel electrode is provided on the first insulating layer in the first opening. The system for controlling a heating and ventilating system includes an input for receiving a demand signal and a heater control circuitry for controlling the heat output of a heat source. An axial channel for passing a rigid logging cable with well-logging instrument is made in the sealing element.