The Standard Poncho is best for birds that like to over-preen their wing-top (shoulder) area in particular. It does offer limited protection for the top of the chest area as well. Each Poncho features a cinch neck that makes it difficult for the bird to get a beak under the Poncho - from the top.
This is also known overseas as the DIY Poncho and that is because the skirt of the Poncho can be trimmed to fit the specific length requirements of your bird.
The Standard Poncho is available in:
Extra Wide which will fit birds the size of a Congo African Grey.
Large/Wide/Wide Plus which will fit birds from Pionus size to birds the size of a Gelah.