Complete with built-in radio transmission wireless functionality, the Speedlite 600EX II-RT sits at the top of Canon's on-camera E-TTL / E-TTL II compatible flash lineup with a powerful guide number of 197' at ISO 100 and 200mm. This revision improves continuous flash performance by 1.1-1.5x, or up to 2.0x with optional battery pack, simplifies the menu system for faster operation, and includes a specially designed bounce adapter, a hard color filter, and an updated soft case. The two-way 2.4 GHz radio system provides added reliability and a range up to 98.4' among up to 5 groups with a total of 15 individual Speedlites. This system also does not need direct line-of-site like traditional optical-based transmission and will work through obstacles. This item is sold as seen for spares or repair. Please read the description in full before purchasing. Spares and repairs items do not come with a warranty but do represent potentially excellent value. All faults or issues are fully described. Cosmetically this item would be placed within our Well Used condition rating. Please Note: This flash is faulty. It's missing the top diffuser that causes the flash not being able to change the Zoom as it's reading it as Wide Panel. For this reason, this item is being sold as spares and repairs.