... filter, Large spot, small spot, hemispot.Technical Specification:Name of aperture Dimension of aperture Dimension of Image Angle of viewRed-free filter F2 ... .4 F2.3 7°4424Large spot F2.4 F2.3 7°4424Small spot F1.2 F1 ... , ±2D, ±3D, ±4D, ±6D, ±8D, ±10D, ±15D, ±20DAperture: red-free filter, Large spot, small spot, hemispotRated voltage: AA alkaline or Ni ...