The Knock Detective is an audio knock detection device stuffed into a 52mm gauge. After bolting the included knock sensor(s) to your engine and connecting the Knock Detective, you can plug in headphones and listen for knock events while tuning. The device also features a bright LED display with configurable sensitivity to help visually monitor knock levels. The user can then connect the 0-5V output to an analog input on their ECU and use it to datalog the knock levels.