This app is developed together with the arrow head manufacturer German Kinetics and designated to be used with Android smartphones. Turn your Opgal Therm-App HZ imager into a bow hunting thermal scope.After attached to the special designed bow mount GKM-1, manufactured by German Kinetics and bore sighted, the app aiming reticle functions allow an intuitive, fast and secure shoot in total darkness.More infos under www.lk-shop.com and www.german-kinetics.com