Liquid cooling is a natural evolution beyond air cooling where either due to thermal requirements or footprint requirements, the desired performance can no longer be economically met by air cooling. Liquid technology is typically selected based on two requirements, the Normalized Thermal Resistance (°C-in²/W) and the Pressure Drop (PSI). Liquid Cold Plates are typically used in many applications such as Industrial Drives, Power Conversion, Telecom, Traction, and Medical. Liquid Cooling is sometimes confused with Heat Pipe Technology. Liquid Cooling has input and output channel unlike heat pipes which use a closed looped system.