16" Heart Shape Double Sided Metallic Foil Mylar Balloons, 10 Pcs/Pack - Silver Heart shape double sided bright color silver foil balloons. They make great party decorations for a variety of occasions, such as birthday, wedding, holiday, Christmas party, New Year's Eve party etc; Size (cm): Approx 41(W) x 41(H) Easy to blow up with a straw. To inflate the balloon with helium: 1. Locate the opening at the bottom of the balloon between the two layers of mylar 2. Slip this opening gently over the nozzle of the helium tank, being careful to not puncture the mylar or the valve inside the opening 3. Inflate the balloon with helium until most of the wrinkles are gone. Do not over-inflate a balloon, which could cause it to burst because the mylar does not stretch Refillable. You can deflate mylar balloons and refill them to use at subsequent events. To deflate a balloon, gently slip a small straw through the valve to open it. Then press on the balloon until it is nearly empty. Suck the last bit of air out of the straw with your mouth so the balloon lies completely flat No need to heat seal. Clench the opening to create a seal; Note: Keep away from fire. Helium expands significantly as it warms up, so fill balloons in an area at the same temperature as your party will be. If your party is in a colder place, the balloons will appear to be deflated, whereas if it is in a significantly warmer location, the helium might expand so much that it bursts the balloon. Do not tie a string around the opening of the balloon. This could cause the balloon to leak Package included: Foil Balloon x 10 (not yet inflated)