Foil balloons come with a self-seal valve, which keeps air from escaping and allows the inflation to last longer.

To inflate with helium, you will need a helium tank with a nozzle or inflator. Locate the filling valve and slide the helium tank nozzle into the valve about 1 inch (2-3cm) and hold the balloon firmly around the nozzle. Fill the balloon to 98% full and remove the nozzle. Gently press around the valve to ensure the valve is closed.

To fill the balloon with air, it is also similar; use the hand pump or electric balloon pump to fill the balloon. If the balloon starts to soften after a few days, gently reinsert a straw and add a little air.