Phottix Mitros TTL Flash for Sony/Mintola Shoe, 4 Channels, Guide Number 58/190, ISO 100, USB Port Full wireless functionality via optical pulses in 4 channels and 3 groups with a range of up to 52.5' indoors Ratio modes from 1:8 to 1:1 and 8:1 are available for firing multiple flash units A modeling flash setting is available for previewing how your shot will turn out High-speed synchronization allows you to fire using the fastest shutter speed available on your camera A bounce card and wide-angle diffuser are built into the flash head for convenience