PERFECT SUITABLE FOR: 66th birthday party, company 66th anniversary party anniversary decoration. You can stick the black 66 balloon numbers on the wall, window or door, you can inflate with both helium or air, you can even place them on the bed, floor or table, provide your birthday party a good display. PACKAGE CONTENTS: 2 Pieces 40 Inch black balloon numberss:No.6 black balloon number + No.6 black balloon number + 1 straw. Material And Use: The black balloon numbers is made of high-quality aluminum film that empty balloon is 42 inch, after filled with helium or air, it's 40 inch. Please use the straw in the balloon set to inflate it slowly. TIPS FOR BALLOON NUMBERS: Due to the thermal expansion and contraction characteristics of aluminum foil, please avoid filling more than 90% of air or helium. If it is over-inflated, it can easily cause the balloon to explode at high temperature. Please avoid leaving the balloons in an outdoor high temperature environment for a long time. If the ambient temperature is too low, it will also cause the balloon to deflate. At this point, you can use the straw to inflate again. SERVICE:we do our best to provide customers with better products. If you have any questions, we promise to give you a satisfactory answer without any delay.