The SweetSpot Pro 2 illuminates a small green LED when you are at your optimum pressure at full-draw, in real-time. If you leak pressure or creep forward, the green LED will go off – signaling you to pull harder. If you pull too hard, a red LED will illuminate, indicating you are beyond optimum pressure. The sensitivity of the SweetSpot sensor can accurately read more than 100 lbs. of pressure and less than an ounce of pressure. The threshold of pressure is completely customizable to your individual setup and personal ability.