1.compass surface diameter:75mm ,100mm ,125mm ,150mm 2.Anticorrosion Strong,shockproof Main Data:Model NO10-75 10-100 10-12510-150Compass SurfaceCompass Surface Graduations0°~360°,0°~360° each minimum is 2°Wooden BoxYESYESNioght Lminous DeviceDC12VDC12VBalancing Ring YESYESYESFriction errorDirection errorSemicircle SwingSuitablet TemperatureRemarksCompass made of pure copper;