Phottix Stratos II Multi 5-In-1 Nikon Receiver 4 groups: A,B,C,D 4 Channels 150+ m range 1/250 sec. sync speed Flash wake-up functions Remote receiver for Nikon cameras and speedlights 2.4 GHz offers a range of over 400ft Connections for speedlights, studio strobes, and cameras Flash wake up system for reduced battery consumption