This feedback is for a chinese 3D edge finder. Unfortunately the X-Y measurement is not accurate in any way and the error varies depending on the axis or by rotating the probe. Errors was overshooting from 0.1 to 0.9mm depending on the direction (probe rotation). Device came with scratches and probe tip had rust (yes it is soft steel). Also the concentricity could not be zeroed because the device would bind if screws were turned far enough. This can be fixed with an eccentric sleeve, but... Seller refused refund blaming the user and his machines. A haimer or low spec tschorn is well worth the 200 (€/$) and very accurate, don't waste your time on chinese 3D tester, no chinese manufacturer can make a decent unit for the same price the germans do.