\"The Knock Box\" Knock Listening device (Duel Channel )

The simplicity combined with the clarity of the \"The Knock Box\" makes this an indispensable mapping tool whether you are an occasional rolling road user, mapping in car or a professional calibration engineer. The Dual Channel \"Knock Box\" Features; Adjustable Fequencey, High quality power and sensor looms (Included), Tough extruded alloy case, High quality noise reduction aviation headset and 2 wide band knock sensors (included).