Nikon SB-600 Speedlight USA Warranty - Basic Outfit - with 4 NiMH Batteries, Charger, Flashpoint Flash Diffuser i-TTL Flash Control: Accurate, seamless fill-flash capability under the most difficult, tricky lighting situations Versatile Wireless functions for up to 3 remote i-TTL speedlight groups controlled by SB-800 Speedlight Four frequency channels prevent other photographers from inadvertently triggering flashes FV Lock (Flash Value Lock) allows photographers to change the composition or zoom for the shot while maintaining desired lighting of the subject Auto FP High Speed Sync Mode when used with D2H Pro Digital SLR delivers needed fill flash in bright light or with wide aperture Nikkor lenses