Instruction: Extract information from the supporting document to answer the given question.

Input:
Question: Very much impressed. But does the hot shoe on the transmitter support through TTL for an external flash mounted on it?
Document: UPDATE: 5/23/2014This is a bad product due to its inability to change flash power when on TTL mode after the user adjusts the camera's ISO. This nullifies the product as a TTL trigger.
If you use your flash off camera then this is for you. It cost way way less than the Pocket Wizard equivalent and the Pixel King pro is much easier to use. If you are a photographer on a budget like most of us are and you want to improve your photography then go ahead and get it. You won`t go wrong. The Pixel King Pro for Nikon ROCKS !! !
I contacted Pixel, and they say these triggers have not been tested w/Yonguo flashes. Yonguo flashes will work with these triggers in TTL mode.
This really doesn't present a problem, as I normally go off what I see in the screen and the histogram.With those negatives mentioned, I will say that with the SB700 the TTL worked very nicely.
This is a shame because the 565 has been pretty nice and works with TTL on camera and off with CLS.A little more research shows that there other flashes that won't work with this unit. So it sort of contradicts itself. It's a bargain-price device that only seems to work well with premium-priced OEM equipment.
press back "SET" button, then pressing side "A", "B", or "C", then having to press buttons on the back of the device again- Plastic cold shoe mount; this could be a problem if the plastic ends up breaking due to fatigue via long term usage and/or mounting the unit on a lightstand in a non-upright manner
Love them. I have two cheetah stand.com lights and guess what, this little gadget allows me full ttl with off camera flash on my D4 camera. I am syncing speeds of 1/8000 f/2.8. Love it no misfires to date..
They were something like $40 cheaper and unlike these units worked fine with every flash I owned. Whatever you buy, insure compatibility with your flashes first. The YN-622N doesn't have an LCD display, but control was surprisingly simple. Still, I added a Debao SU-800 to the YN-622N and now have a user-friendly interface to the control compensation levels, as well as a simple setup for Nikons CLS if desired.
i've had the pocket wizard 'flex' system for about a year and rarely got it to work with my nikon flashes. a friend of mine has the same problem. this product looked kinda lame, but guess what, it works flawlessly.
The product is excelent, I have one Pixel king 2nd Generation and never have any miss-fire, and now I bought the Pixel King Pro 3rd Generation from Amazon.com, and when I turn on my King Pro fourth time on of his line of LCD panel never turn on...Now I don't know how can repair this product.Because I'm from Paraguay and I can't send to the warranty.
Answer: Yes, it does support through-ttl according to the company.  I've tried it a few times and it worked, but frankly it becomes a little clumsy unless it is used on a tripod.