0 V- j: I3 w/ U6 c iPhone4 Power Portable Back Up Battery Case (1400mah) ' O2 L5 r. c: ^$ u4 j) Q 4 ]1 X2 H* h3 U0 g $ b7 B, N1 N& [8 n U+ N : Y N+ R8 u$ I& `9 O' j8 iThe Youtube video shows you how the back up battery case works for your iphone 4: http://www.youtube.com/watch?v=SRntwhMckB4&feature=player_embedded