This is a function that is available to compare similar products. UDesign theme creates compare page when you install WooCommerce. You can choose the best product in terms of comparable products with price, ratings and so on.

Compare is enabled in Theme Options > Features > Compare.

Compare Popup Type option is to set the popup types of compare when you click compare button. UDesign supports 2 types –  mini popup and off-canvas.

Products Max Count option is to set the number of products that are able to show off in Compare page. If you input 4, then 4 products are displayed.