In addition, the size of balloons seems to vary. Some said deformation is very extreme, at other "only" strong. Could also explain why some balloons have burst.
If the balloon should be nicer not to long or not fly, I would rather take up this balloon:
Karaloon G11099 - 100 balloons 28cm sorted,
If they are to fly long you can use under certain conditions the "30cm" balloons here. In such a case I would advise rather on the Karaloon balloons of links.
I have a real torture with helium-filled balloons behind me.
Starting with the Karaloon with clearly short flight time, I ended up here after months test phase at this. Absolutely not convinced, but inevitably nonetheless ordered several times. Since it was very difficult for me larger balloons to find long fly. And many were consumed during testing.
My balloon should fly a week without problems. As guests on days distributed came to me. And of course, they should also fly to the celebration, which is why I have used ultra high float. As a total beginner with float and helium filled balloons it was very difficult, especially since I had begun unknowingly for weeks with little to Karaloon.
I then handled the 30cm balloons with Ultra high float about a day before the arrival of the first guests and inflated to 30 cm with helium. So then when the guests arrive have a beautiful shape, because they are smaller unverhinderlich. Total Schwebdauer the balloons with Ultra high float in a closed room with no problems 10 to 16 days ago. Outdoors they floated unfortunately much shorter - sometimes not even five days (. Perhaps because of more bad weather including some rain).
Because it has still to some extent worked at the end, I forgive well meaning 2 star. Because of ugly form at 30cm inflated balloon and the questionable quality because some burst, etc.