The 545-190 tilting level combines precision with rugged reliability for the most demanding leveling jobs. Accuracy is maintained at ±0.001" (0.025mm) from two inches to 17 feet (50.8mm to 5.2m) and one arcsecond from 17 feet to infinity. (This info from Brunson) Please NOTE: $100.00 re-calibration fee added to first rental invoice.