The Canon Speedlite 550EX flash unit is a powerful and versatile high-end professional flash unit designed to meet the rigorous professional specifications for both professional and advanced users of EOS series cameras. Weighing 405 grams, this flash offers numerous advanced features, including the wireless Autoflash mode with automatic ratio control for up to 2 slave groups and 1 group for flash exposure compensation. In addition, with the Stroboscopic function, up to 100 consecutive shots can be taken at a rate of 1 to 199 flashes per second. The flash can be tilted from -7 to 90 degrees and rotated up to 270 degrees for greater versatility. You can also manually adjust the flash output from 1/1 (full) to 1/128 (8 stops) to control the intensity of the light emitted. The Canon Speedlite 550EX is a valuable ally in achieving professional results when shooting photos.