Don't waste your money on silenx. They are nowhere near what they're rated for. They claim 90cfm and 14 db, for merely $30 per fan. No fucking way. Don't waste your money. www.jab-tech.com buy the Yate Loon D12SL12. Very quiet, rated properly, individually balanced fans with no squeeking, scraping, scratching, rubbing, ticking. MUCH nicer than a silenx.