This is a good vest to be visible at night for a cyclist or a pedestrian.

This size (XL) fits those who usually wears L-sized men's t-shirts.

The very same item as below:
http://www.amazon.com/gp/product/B0086X6SIG/ref=oh_details_o03_s00_i00

I usually wear M-sized t-shirts and found this too large, so I bought their L.

Available in Stanford or Menlo Park.