Ikelite Autoflash AF35 Kit, Right Hand Flash Kit with Extended Tray for Dual Strobes- Guide # (ISO 100) feet: 28 Surface, 16 Underwater Strobe Size: 8cm x 12cm - 3.2" x 4.7" Weight: 0.6 kg - 1.3 pounds Energy Rating: 35 watt-seconds Coverage Angle: 70 - 80 degrees w/diffuser Guide # (ISO 100) feet: 28 surface - 16 underwater