The Block Party Mylar Balloons are the perfect way to make a kid's birthday party come alive with color and fun. With 10 packages per case and each package containing 1 balloon, each case contains 10 balloons for a total of 10. The 18" balloons are made of mylar and are decorated with lock blocks in a variety of colors, sure to add a festive atmosphere to any birthday celebration. Use them to decorate the party venue, bunch them with latex balloons for an extra pop of color, or give them out as party favors to your guests. Make the special day even more special with the Block Party Mylar Balloons!