For decades professionals have used our One Stop Switching Flash Head for less illumination from their main light source.This could be for a fill light, a hair light accent, to illuminate a background,or where ever creative use that comes to mind.The 2110C,at full power,shares an equal portion of the light,from the other head plugged into the same pack.It can be switched off,too.The modeling light switch adjusts independently from the flash. The 1000 watt/second flash tube is color balanced to 5500 degrees Kelvin. The 100 watt Tungsram modeling lamp is very affordable. A 25' heavy duty cable is a manageable length. Flash Ratio/Modeling Switches Full<Off<-1stop Flash Tube 1000w/s-5500 degrees Kelvin Modeling Lamp 4101-100 watt Tungsram Cable Length 25 Feet Weight 1lb-11oz. Size(WxDxH) 6-1/2"x5"x6-1/2"