An indespensible tool when shooting with multiple flashes. There are other companies who make slaves, some radio, most optical, but none come close to the performace of these. They can be triggered up to 1600 feet away, which is fun when you see someone else shooting with them and you tap into their channel and fuck with them. The new models are called ‘Transceivers’ meaning they can be both transceivers and receivers. And you can plug two flashes into one unit (although sometimes this doesnt work; to fix this problem, buy a headphone splitter so that one socket turns into two. But the splitter has to be a mono to mono/mono splitter, not to stereo/stereo.) They come with standard PC-to-miniphone (1/8″) cords, which you can use to plug them into your camera if you don’t want to/can’t use your hotshoe.
Accessories– You will need to get cords that are compatible with the flash you will be using them with. Most Sunpak flashes use a plug called ‘household’ which looks just like a plug you would plug into a wall (in America). Vivitars have a special plug, which is small and pointy (and unreliable).
You can find these on eBay for around $160 each.
*PocketWizard Plus I models are compatible with the Plus II transceivers.
**It is possible to fire two flashes with one PocketWizard unit using this plug.