OTTO’s Bluetooth Revo NC 2 with HD audio this speaker mic is no toy, it’s a professional, rugged tool for law enforcement. It features a revolutionary patented noise-canceling (NC) microphone for optimum voice clarity even in high-noise situations. The speaker mic works with portable radios, cellular phones and mobile radios as well. The Bluetooth Revo NC2 has a battery to outlast even the longest shifts and large and rugged buttons, there’s no fear of self-actuating.