Hello,

As it is suggested in the information written below the option. You can read that to get better understanding:

“In this situation, some of the products will be twice bigger in width than others. Recommended to use with 6 columns grid only.”

So, if you want to use that option on your Site try to make sure that you have 6 Columns selected for the Products Grid under the Theme Settings and then you can achieve that like it is mentioned in the Screenshot.

Further, you can check the Theme Documentation guide on Image Size and Content Alignment too (if it is of any help to you): https://xtemos.com/docs-topic/image-size-and-content-alignment-in-a-product-grid/

Best Regards