Elicar automatic TTL ring flash with dedicated ttl hot shoe for Nikon film SLRs and early digital. Doesn't work with latest D700. Power unit takes four AA bateries and slides on camera hot shoe. The ring flash is light so no strain on the lens and plugs into the power unit. There's a ready light on the unit and the back of the flash. The flash has a modelling light that can be switched on when needed. Thyrsiter circuit delivers a fast recycle time.