Our 18" Block Party Mylar Balloon is the perfect addition to your birthday block party decor! The block party theme is perfect for your Lego lovers next birthday, or anyone who loves to build! This square-ish shaped mylar balloon features a fun building block pattern that's bright and vibrant and sure to make your birthday block party pop with color! A great option on its own, or you can add other mylar and latex balloons for a bright birthday bouquet or centerpiece! Sold uninflated.