Vintage J.Crew Outfitters Oarsman tag short-sleeve crop sweater polo is made from a lightweight, open-stitch knit fabrication. 
It features a three-button placket, classic ribbed collar, and relaxed drop-shoulder sleeves in a soft pastel pink hue.

Nice vintage pre-owned.
Please see photos for the details/measurements to ensure proper fit as size tag may vary between brands/styles.