If I get this do I need anything else to control my flash units? I have a 580 II EX and an Alien Bee 800
Buff Flash Units - Q&A...
Q: What will trip the built-in slave tripper?
A: The built-in slave tripper in each flash unit is designed to sense flashes of light and fire the unit simultaneously. The tripper is sensitive to both visible and infrared flashes of light. Any light flash that it “sees” can trigger it, including the flash from another unit in your setup, a conventional on-camera flash (and its pre-flash), and/or an infrared remote transmitter. Although this gives you more options for triggering the lights in your setup, the presence of extraneous triggers must be considered when you are not the only photographer in the area. Other photographers' flash units, on-camera flashes (whether on professional or even disposable cameras), and infrared remote controls can inadvertently trip your flash units.
When you are the only photographer in a specific shooting environment, the built-in slave tripper on each unit eliminates excess wiring in your setup. You can use multiple flash units and hardwire just one unit to your camera. Your camera’s sync circuit will fire the hardwired flash, and the built-in slave cell on each of your other units will fire the remaining units simultaneously.
If you are shooting in an environment where other photographers are using flash units, you will need to disengage the built-in slave tripper in your flash units.