You are looking at a unisex Nike reflective running vest in a size S/M. This gray w/black vest has an adjustable strap at the waist and is 94% polyester 3% cotton 2% rubber 1% nylon, machine wash warm.
As anything goes with Nike products, this is a great reflective vest. The first few times I wore it, it did not move on me at all and stayed in place very well. The more I wore it, however, it started to move and shift on me as I was running. I got this to use for night runs, and the reflectivity is great. It washes very well also. Sizes are true to size and is really a good product.