Our 6.5mm Coin Flex Tiles - Designer Series are UV Stable. The main differences between the standard and designer series versions are sizing, interlock, and colors. The interlock on our the designer series is the best on the market with at hidden interlock technology that does not allow water to flow between the tiles. Also, the number and variety of colors available are superior to the standard version allowing for more customization. The sizing of the tiles would be negligible since these tiles can be easily cut to fit any room size.