With full support for Olympus/Panasonic TTL, including high-speed sync, and a built-in 2.4GHz radio system, the Godox TT685O Thinklite TTL Flash will make it easy to create both simple and elaborate lighting setups. When mounted on camera, it is an effective lighting tool with a powerful guide number of 197' at ISO 100 and 200mm, a zoom range of 20-200mm, and the ability to tilt from -7 to 90° and rotate 360°. As a TTL-capable unit, the TT685O can also operate as a full wireless master or slave unit with TTL functionality.Operation is intuitive with a rear LCD panel that shows settings. Also, the flash is equipped with a Wireless Control Port for attaching an optional remote control set and it has a 3.5mm sync port for basic wired connectivity. It runs on four AA batteries, which help provide a recycle time of 0.1-2.6 seconds.An integrated 2.4GHz X radio system is incorporated into the TT685O for wireless triggering. Able to be set up as a master or slave, this flash will help you create a versatile lighting setup with a range of 328' and support for 32 channels and three groups. It can also work with an optional X series transmitter for creating more elaborate setups.Being compatible with Olympus/Panasonic's TTL system, users will enjoy numerous automated flash settings and the ability to use functions such as high-speed sync.With a guide number of 197' at ISO 100 and 200mm the TT685O will easily illuminate most subjects. It also features a zoom head with a range of 20-200mm and a 14mm wide-angle panel for using a variety of different lenses.Manual power control from 1/1 to 1/128 in 1/3 EV steps.The flash head can be tilted from -7 to 90° and rotated a total of 360° for controlling bounce and where the light falls on the scene.Optical master/slave transmission is available for working with other standard flashes.Using an optional FT series remote control set, users can connect to the wireless control port to gain wireless control over the flash's power settings.A 3.5mm sync port is available for setting up a wired connection to a camera or trigger.This flash runs on four alkaline or NiMH AA batteries which help deliver about 230 full-power flashes and recycle times of 0.1-2.6 seconds.USB connection for installing future firmware updates.