Detailed Product Description Photoelectric Beam, 4 Beams, 50M. Digital Frequency Conversion.Photoelectric Beam, 4 Beams, 100M. Digital Frequency Conversion.Photoelectric Beam, 4 Beams, 150M. Digital Frequency Conversion.Photoelectric Beam, 4 Beams, 200M. Digital Frequency Conversion.Photoelectric Beam, 4 Beams, 250M. Digital Frequency Conversion.