Nikon SB-400 AF Speedlight Flash for Nikon Digital SLR Cameras Compact, lightweight Speedlight unit 18mm angle of coverage with Nikon DX format digital SLR cameras Bounce capabilities in 4 steps up to 90 degrees; flash shooting distance range from 2 and up to 66 feet Approximate guide number of 98.4 feet at ISO 200 (at 18mm zoom head setting) Operates on two AA-size (1.5V) batteries; fast 2.5 second recycling time