I usually wear oversized t-shirts so I ordered a large one. It was a bit big so I ordered a medium. When the medium one arrived it was exactly the same size as the large one so I ordered the small one. When Small came out, it was exactly the same size as Medium and Large. There is only one size, they are simply marked SML. Since I only use them for gardening it doesn't really matter, but they are all the same size.
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