This gives you the Prestige Shamrock Rank in game & the Saint Patrick's Top Hat. You can see an image of the Hat by viewing the image below, equip it in game by using /cm and clicking the hat you wish to use! The Shamrock Rank grants a Light Green -> Dark Green chat gradient in game when equipped and is only available until the 15th until leaving the store and being replaced by the Shamrock Rank. The Prestige Shamrock Rank comes with a Gold Star! Flex on others who weren't quick enough!!! It also comes with a Shiny Hat! 
You can equip your rank in game by doing /ranks, clicking Cosmetic Ranks and scrolling over to Prestige Shamrock Rank. You CANNOT equip two ranks at once. If there's any issues, feel free to open a Ticket on our Discord describing the issue.