Aluminium Case Bullseye Spirit Bubble Surface Level Round Inclinometers for Surveying Instruments and Tribrachs, &Oslash;60mm ,Accuracy 15'/2 Aluminium housing.High quality plastic vial Applications:Precision Instrument Levelling .High precision weighing scales.Robotic systems levellin Sensitivity 15' per 2mm bubble movemement High impact Alloy metal body High contrast bubble.Wide temperature range . NOTE: NOT USING IT UNDER THE Strong Sunshine.