Carbon Express String Tracker?
 

Just checking out gear online wondering if anyone has used this and if so does it work?

http://www.keystonecountrystore.com/...g_Devices.html

Have used them for several years as I hunt alone and usually end up in thick stuff, also am not the worlds best tracker with old eyes and bifocals. They work good but have limitations; 1 - some drag on your arrow, so check and adjust before using for real, 2 - tie the string to your arrow by loosening the head and tying around its shank and screwing back in, the instructions say to just wrap it but if the head loosens(probably will) the string comes off, 3- have had the string get cut by bone or broadhead after the hit but even then you get a general idea of what diection to look in. have found two deer that I would never had found, one doubled back with no bloodtrail, was following the tracker string and saw off to my right about 10 yards the string headed back in the opposite direction. The second I hit back in the liver and went about 300 yards thru cedar and swamp brush and changed directions about 6 times, the string finally snagged and broke but I had a blood trail for about 25 yards to where it lay. The string is really strong and will take a lot to break it. I usually go back and pick mine up after the fact so something doesn't get snagged, and when you start pulling out of the brush you find out how strong it is. So if you go alone and are not an Indian tracker and shots are around 20 - 30 yards give it a try, works for me.

As 421x3 said, you have to shoot shorter distances. I think that is why they make sure to say limited distances in the description. I tried a different brand years ago and did not like the string drag on the arrow flight. Also, my shot opportunities where I live are usually longer. I can definitely see the advantage if you are hunting tight cover.