I’m a born skeptic. The description of float time extensions with Hi-Float seemed too good to be true. So I did a test, inflating two of the same balloons at the same time with the same amount of helium. The balloon without Hi-Float lasted the typical eight to ten hours, dropping to the ground by the end of the day. The second balloon, filled with Hi-Float is still happily floating in my living room an unbelievable seven days later. The inner coating Hi-Float adds to a balloon works best in an environment without expansion and contraction from changing temperatures that will cause the coating to be compromised. Meaning, a balloon outdoors in the sun and wind would still have significant extended float times but understandably wouldn’t be able to match times of those indoors. Either indoors or out, Hi-Float does exactly as described. The price per balloon is economical. Try Hi-Float, you won’t be disappointed,