The set contains: 2.2 l helium disposable cylinder at 110 bar pressure, inflating valve, 30 balloons,made in natural rubber latex which will not rapidly deflate unlike the rubbish bought in the likes of Mr Price, Cardshops etc - 25 cm diameter each, 20 m balloons strings. ATTENTION: each helium gas cylinder (242 l) can fill the 30 balloons included in the set. The floating period in the air is between 8 and 12 hours and depends on the ambient pressure and temperature.