This item is an accessory. It must be rented with a non-accessory item.
If you are using a Sony camera with the FJ-X2m Universal Flash Trigger, you will need this adapter.
Unsure if the Westcott FJ400 strobe system will work for you?
Westcott has a pretty good ongoing Q&A section that covers some of the more specific features and what they can do. We strongly recommend checking this invaluable resource if you still are not sure if this strobe works for your needs.
Strobe Trigger - Westcott FJ-X2m Sony Adapter (4711)