This t-shirt is in new with tags condition and has not been worn. This shirt is 100% authentic. It's tagged as a Japanese size medium, but it has a relaxed fit and fits like a spacious US medium. Here's a sizing chart for reference:
Chest width (pit to pit)- 22.5 inches (57 cm)
Length- 29 inches (73.5 cm)
Shoulder width- 20.5 inches (52 cm)
Sleeve length (from the shoulder)- 24.75 inches (63 cm)
Sleeve length (from the back of the neck)- 35.5 inches (90 cm)