Guide no: 34 at 85mm focal length on ISO 100. Flash Range: 12 Metres Approximately at F2.8 depending on the lens Auto Aperture Setting. Manual Bounce head at 28, 35, 50, and 85mm (30 45 60 and 90 degrees) Flash Readiness Indicator Synchronaisation on the 2nd curtain, depending on camera Power saving function Power Source 4 X aa 1.5v Battery