My birthday gift from my wife arrived a little early. I told her I needed an external flash with TTL capability for Fuji X cameras. She didn't know that meant but she wrote it down and a phone call to an on line photo dealer netted this EF-42. The EF-42 or electronic flash 42 is named after its guide number of 42 meters at ISO 100 at maximum zoom. It is reportedly manufactured for Fujifilm by Metz. The unit is fairly small and light (weighs about the same as 4 alkaline AA batteries) and very simple to use. I find it surprisingly powerful for a unit of thies size and weight. It provides selections for TTL or manual operation, zoom level and exposure compensation. That's about it and about all I need. The head tilts for bounce flash and rotates for wall bounces or vertical orientation ceiling bounces. Like all flash units the EF-42 has an LCD screen and a few controls on the back. There are two main controls. Mode moves around the screen to land on a function that you want to change. SEL steps through the options for that function. The MODE button also handles some of the selection duties in exposure compensation adjustments. There is an on/off switch and lighted button that fires the flash manually and indicates a fully charged state. The unit turns off automatically when the camera is turned off and turns automatically as long as the on/off switch is in the on position. The screen indicates mode (TTL or Manual,) lens found, exposure compensation and a digital rangefinder. It also provides details for your manual mode settings. The unit zooms automatically to the correct point based on the lens in use. There really isn't much more to it than that. For those of you who, like me, never ever mount a flash unit on a camera you can use any Canon compatible TTL extension cable to get the flash unit away from the camera. I picked up a Neewer Canon compatible coiled extension cable for $12 on Ebay. It works perfectly with full TTL functionality. There are more functional and complicated flash units in the industry - even one from Fuji - but if what you want is a powerful, well made and simple-to-operate flash unit that mates perfectly to the electronics in your Fujifilm X camera, the EF-42 may be just the ticket for you. My wife did a great job. I like it and recommend it.