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 vials are calibrated at 0, 0.5, 1.0, 1.5 and 2.0 in the level so slopes are accurate, fast and easy to measure. 48 inches. Has four solid acrylic horizontal vials measuring slope at 0%, 1%, 1.5% and 2%. Accuracy: 0.0005 in. per in. (0.5 mm/m) on all vials.