This is an Elinchrom Ranger RX AS 1100W/s Kit with Ranger A Flash Head The "RX" signifies the ability of the power pack to be fired by a remote control handset, or computer. The "AS" indicates the power pack"s ability to divide the power asymmetrically between two attached flash heads. Also improved, is the power range selection: 8.5 f/stops. Lower the power to 5.5 w/s, and switch to slow recycle and up to 5100 exposures can be made. Elinchrom Ranger has flash durations as short as 1/4310 sec. (with 2 "A" heads attached), ideal for sports, fashion, and theatre photography. Controls on the pack permit changing the output in 0.1 stop increments in an easy-to-read digital display. This is a 1 head kit which includes a Ranger "A" flash head. "S" Heads produce a "Standard" flash duration. The "A" for Action heads provide ultra-short flash duration. Please note: Product specifications are subject to change without notice. This kit does not include a reflector.