PENTAX AF 540FGZ Flash Compatibility: K-series DSLR cameras, *istD-series DSLR cameras, Pentax SLR film cameras. Guide Number: 148 ft. / ISO 100 AF-assist Beam: Includes an autofocus assist beam for focusing in low light or low contrast situations Power Source: 4 x AA batteries Dimensions: 3.0 x 5.6 x 4.2 Weight: 13.04 oz. (without batteries)
