Specs Outlet 2 pole 3 wire grounding 20A 125V Wire Insert Accepts 4 X 10 Gauge wire allowing for easy flow of high current 2ea MWA Caps included in package : The original Magnetic Wave Absober, MWA series, was released in 2009 and become very popular for its sure effect against noise generated by electoric magnatic wave around equipment. MWA-EC. we applied this MWA material on the top of receptacle cap for preventing EMA, noise, and dust altogether with very easy usage. Just plug it into the receptacle hole.