The Macrolite ML-1 is an electronic flash system designed especially for close-ups with the Canon A and T series manual focus cameras and lenses. It consists of two twin flash,which ca be fired together or individually to create different effects. It is especially suited to be used with the Canon 50 and 100 mm macro lenses for medical or dental photography.Requires 8-"AA" 1.5 volt batteries.Weights 1 lb 6.4 oz without batteries.