Ever have concrete installed only to have water pooling right where you don't want it - like in front of the garage door. A gradient level can help! Kapro's Top Grade Gradient Level was designed specifically for this purpose and is easy and literally fool-proof to use. Its three vials are each calibrated at a different percent 0%, 1.0% and 2.0%. Depending on the slope you require is the vial you read so slopes are accurate, fast and easy to measure. Gradient, Ratio, Pitch and mm/m conversion for each percent is clearly printed below each vial. 1 solid acrylic vial. 24 in. Milled surface. Accuracy: 0.0005 in. per in. (0.5 mm/m) on all vials.