This battery grip takes 2 EN-EL3 battery packs and is ideal in situations where a large number of shots are to be taken or in low temperatures. At the bottom of the grip there is a tripod jack for fixing it with a D50 on a tripod. It comes with a detailed English instructional manual showing you how to install it on the D50. With this battery grip, long hour shooting is no more a problem! This is a professional one different from other D50 battery grip! With this one, the user can make vertical shutter! There is an infrared signal transmitter on the grip (see picture 6 above), it can trigger the D50 easily, and before using, the camera should be set on IR mode! What does IR mode mean?