BLACKWIRE C310 Bulk Pkg -85618-02 USB Headset are a simple-to-use comfortable and durable choice for conference calls Web-based training and PC multimedia applications. Inline controls make it simple to answer and end PC calls and control volume and mute. Noise-canceling microphone filters out background sound. SoundGuard technology provides protection against audio spikes and Smartly placed indicator lights and helpful audio alerts give call mute and volume status.