Remove Check Box from Single Item

First, love the plugin. It was perfect for what I needed to do which is offer a free PDF download with purchase over a certain amount.

Being as there is just a single item to choose from is there a way to remove the check box for the item? It should be enough to just “Add” or “No Thanks” without having to select the single item.

Thanks again..

https://wordpress.org/plugins/woocommerce-multiple-free-gift/