projector be small , fit in place of battery cover . be careful , projector do not fit as well as cover , so take care not to break or scratch contact when fitting it to phone . Projector fire up immediately when slide lens cover to reveal projector lens . very easy to use . focus be a slider on the side of projector . can toggle landscape\/portrait by press the phone 's camera button . image be brighter than I expect after read many other review . Easy to focus . do use up battery life pretty quickly , so if you be not use external charger , monitor you battery life closely .