The monster power blackout high definition powercenter hdp 900 is a bold combination of design, engineering, and convenient functionality. it"s designed to give your delicate hdtv and digital av electronics the advanced surge protection they need. the hdp 900 also features hd clean power noise filtration for better performance. the hdp 900 gives your delicate hdtv and digital av electronics the advanced protection they need. for a triple layer of safety, the hdp 900 protects against power surges and spikes on all three power lines (line, neutral, ground). cell phones, tvs, appliances, and other electronics all generate noise and interference that pollute your home"s electricity. this dirty power can degrade picture and sound performance. dirty power can also stress the delicate digital circuitry inside hdtvs and other home theater components, potentially shortening their life. however, ordinary surge protectors can"t remove the effects of dirty power.