naturally when the power is seperate from the tubes, it makes easier pack travel. I have used the Balcars before and really liked them. They got old and sold them. Since I have had Norman with just about all their variety of packs, and they are build strong. Only issues were after user accidents. Now I have Photogenic mono's and I am very happy. they have upto 1000w/s, Oddly enough Norman and Photogenic and Giodard are all the same company, and you can get adapters to work from Norman modifiers to Photogenic heads. The only thing with these and the Balcars, or even the Speedo's, the flash durration I dont think is very fast. Sure some better than others, but I would THINK the D1 is much faster. Calumet and another company with V, Vistatek? or something, I think use many same parts.