The Nikon SB-400 Speedlight is an intelligent and versatile external flash unit that provides i-TTL flash operation in a super-compact and ultra-lightweight body at an affordable price. Features: Designed as an entry-level external flash, this flash is ideal for the compact D-40 digital SLR camera, but it is also useful for hobbyists and professionals looking for a handy i-TTL flash unit offering an effortless bounce flash function. When combined with cameras that are compatible with the Nikon Creative Lighting System, the SB-400 is controlled in i-TTL and D40's M (manual) mode. Compact, lightweight Speedlight unit Simple, intuitive operation; Put it on, turn it on and shoot! 18mm angle of coverage with Nikon DX format digital SLR cameras Utilizes Nikon's i-TTL intelligent flash Operates on two AA-size (1.5V) batteries Fast 2.5 second recycling time Bounce capabilities in 4 steps up to 90 degrees Approximate guide number of 98.4 feet at ISO 200 (at 18mm zoom head setting) Flash shooting distance range from 2 and up to 66 feet Compatible with all Nikon Creative Lighting System cameras