This NSK 4000 II case is designed to meet Intels Thermally Advantaged Chassis (TAC) 2.0 design guide requirements. Higher energy efficiency reduces power consumption by up to 25%, saving you money on your electric bill. EarthWatts power supplies have achieved 80 plus certification, the highest independent standard in power supply efficiency. In addition, EarthWatts includes a variety of protective circuitry: OPP (over power protection), OVP (over voltage protection), and SCP (short circuit protection).