Nikon SB-600 Flash Gun. This flash has a guide number of 30/98 [ISO100,m/ft], 42/138[ISO200,m/ft] (at 35mm zoom). The SB-600 supports i-TTL (for automatic balanced Fill-Flash), D-TTL, TTL, Manual. It features a easy-to-view LCD with 6 simple-to-understand backlit buttons. This flash is in very good condition, coming with full instructions and soft pouch.