... use for 5~6 hours compact, handheld model - one hand operation. microscope type: Binocular crossed stereo microscopeTotal magnification:eyepeice 10X ... 0mm~ 10mm continously adjustableSlit height: 1mm, 3mm, 5mm,10mmDiameter of light spots: 1mm, 3mm, 5mm,10mmFilter: Heat absorption, gray, Redfree ... 18VA Net Weight 750g, portable for carry,with four light spots, equip with all functions of a desktop slit ...