They look like this. The bottom has a 104" circumference, and it is about 50" from the bottom of the hood to the bottom of the back.
I'd like to see one made of a lighter material, but oddly enough, the shower-curtain like material it is made from is actually stiff enough to not make it drape too much on you.
The front has five snap closures starting at neck level and leaving the last 10" or so unfastened on the bottom. The arm openings have two snap closures as well dividing the arm opening into thirds. The hood has several snap adjustments to all it to be secure and not used or open enough for a helmet or open enough for use without a helmet.
If you don't need to use your arms, the arm opening can be snapped shut for max weather protection. With the arms and top neck portion secured, it holds in more heat.
Since it is somewhat conical shaped, it lends itself well to fastening over and end of a hammock and held up with the ridgeline. This will keep more than 50" of your hammock shielded from any elements.
The fabric is so tough that I've also used it as a ground cloth under my hammock for storage.
Hope that helps some WV.