The flash unit is konzipert as an additional flash for cameras that do not have a standard flash hot shoe connection and is ignited by the built-in flash of the camera. The Electronic overcomes making sure the / Before the (measured) lightning (s) or anti-red-eye flash and ignite at the right moment when you shoot. The prerequisite is that you with some test shots "anlernt" electronics. This works reliably, METZ called just a few exceptions (NIKON 3D and D-TTL and cameras with varying number of pre-flashes). Different modes (Auto-Manual-Easy) allow adaptation to almost all lightning conditions and cameras types by adapting ASA and aperture, the guide number 22 at 100ASA ensures the illumination of even large spaces, either by intent discs (Tele-Wide), the flash to the focal lengths of 24 - 85 mm to be adjusted (according KB24x26). In Easy mode no adjustment of ASA or diaphragm is provided, this mode is intended for cameras that do not have adjustment. Here the flash output with the help of test images is optimized according to a 20-point scale. The battery requires micro-AAA batteries, NiMH batteries are to be used without problems, however, only be recharged externally (charger not included). For the number of flashes per set of batteries / battery I have no experience yet, METZ called 100 flashes. For mounting on the camera is a rail with standard tripod mount, but the unit can also be installed completely free in space. The compact and handy device is a highly recommended addition to usually quite weak built-in camera flash, not only for Digi cameras! The device works reliably and fits my expectations, I am very satisfied. A highly recommended purchase.