Compact Bounce & Swivel Flash (i-TTL) For Nikon D3100 Dedicated flash for Nikon D Series has vertical bounce Range of 0 - 90 and horizontal swivel Range of 10 - 60. Autofocus auxiliary lamp helps the camera to focus in low-light situations Includes diffuser Guide Number, (Formula): 32, (Guide Number = Distance  f-number) Power Source: 2x 1.5V "AA" batteries (alkaline, lithium, NiCad & NiMH) - NOT INCLUDED