Works! Not much instruction.
928123
Working great in a 2007 Corolla with the A51813 radio (printed on face of radio).  Caution--radio face is connected to radio body with small,delicate ribbon cables!  Also, really need to remove center dash piece to get radio out (see youtube videos).  Adaptor seems to work great--hit "CD" twice to switch to what radio thinks is external CD-changer, but is this.  Case, cables, etc., are fine, but light-construction (cheap).  Assume this will work fine for foreseeable future.  Much better than the FM-modulator the "pro" installer put in this car.  There were no instructions to speak of with the unit.
637109
Seems to work ok, but instruction sheet leaves a bit to be desired - illustrations with simple captions - some interpretation of intent is required.
1579162
It didn't come with many directions, but the diagram in the amazon page for the device was sufficient.  I got it working with a Raspberry Pi.
265489
works fine, could have come w/a little documentation or link to official documentation.  Had to google and piece together how to wire it.
3837210
Product works great  but it didn't came with instructions so I had to source it out through website..other than that it's cheap and it works
2932024
With a set of decent tools to open my Mac Book Air this part was a straight forward install. No detailed instructions so not good for a newbie first project. However, part fits well and works! Recommended!!
4301373
Works well - No instructions but easy to figure out - survived one trip so far.
3798433
Works well.  You will need to find a youtube video for instructions.
4158822
Solid quality, no instructions!  Simple instruction would have been nice.
3451006
Great! Except no instructions on how to set it up. But you can find instructions on youtube.
1975905
works as advertised. clearer instructions would be better as setting it up is a bit of a juggle, possibly a video showing how. (if there is a video, somebody please tell me as I'd like to know if I've done it correctly!).
4928532
Works well for the price. Instructions are poor.
961549
Works well but needs an instruction sheet.  Use is not that intuitive.
4502897
This product didn't come with instructions... I get the general idea, but I guess I will be searching YouTube for instructions.
672917
Worked just like I needed it to. No instructions. But I did find a video on Youtube that helped me figure it out.
3397889
It sure would help if it came with instructions.  Piece of junk!  Don't buy it.  You get what you pay for.
4958348
Works as advertised.  Instructions suck, if you don't know what you're doing go to youtube.  The pins are color coded, but the colors are hard to tell apart.  The included tools are poor.  Use a 1/2 hardwood dowel as a plug follower, instead of the included hollow plastic one.