The screw-on lid is a single piece and not two parts like the traditional mason jar lids used for canning. It has a rose filigree pattern cut into the top for a unique decorative accent for your mason jars and a hole in the center of the pattern that allows you to conveniently use with a straw. The white tin metal straw lid has a diameter of 2 3/8”, perfect for the 8 oz. favor jar, cactus-shaped jar glass, and both the 12 and 16 oz. sizes of our custom printed mason jar drinking mugs. It’s a cute, cheap-priced add-on. Straws are sold separately.