Balanced flue gas fires vent directly through an external wall by means of a horizontal co-axial pipe (one pipe within another). Air is drawn in through the outer pipe, and combustion gases are expelled through the inner pipe. Balanced flue fires do not require an electricity supply.alanced flue gas fires vent directly through an external wall by means of a horizontal co-axial pipe (one pipe within another). Air is drawn in through the outer pipe, and combustion gases are expelled through the inner pipe. Balanced flue fires do not require an electricity supply.
A keyboard which is connected to the computer by use of a USB cable. A keyboard which is connected to the computer by use of a USB cable.
USB hub. A USB hub is a device that expands a single Universal Serial Bus (USB) port into several so that there are more ports available to connect devices to a host system, similar to a power strip. USB hubs are often built into equipment such as computers, keyboards, monitors, or printers.