There is no size chart. How do I choose size?

For heated jackets, you can see the size chart by clicking the "Size Guide" on the product page.

For our heated vests, most of them are size adjustable, suitable for S-XXL. The adjustable vest comes with a set of size panels(6 pcs), 3 pcs panels for each side. Simply unzip the zippers under each arm, and replace the panels as needed to adjust to your size. Smallest size doesn`t need any extra panels at all.😄