The YN685 Wireless TTL Speedlite from Yongnuo offers complete radio slave functionality with both the YN-622C and RF-603/YN-560 radio systems for maximum compatibility with your existing gear. The flash is also compatible with Canon?s E-TTL / E-TTL II flash system when mounted to the camera and has a powerful guide number of 197? at ISO 100 and 200mm. Benefiting this power is a wide zoom range which will cover 20-200mm in full frame, and a diffuser for wide angle lenses. It also features full bounce with tilt up to 90? and rotation of 180? to the left or right.