Smile transfers a portion (0.5%) of the sale to a charity of the buyers choice. You can't force or even suggest one in the link and it only applies to smile.ama

Smile transfers a portion (0.5%) of the sale to a charity of the buyers choice. You can't force or even suggest one in the link and it only applies to smile.amazon.com links. I think St Jude's is the default though so they may come out ahead if you change the URL.