Crystal Clear Aqua Balloon - perfectly round, stretchy long neck.

For this 125mm Aqua balloon, the minimum recommended filling size is 130mm and the maximum filling size is 230mm. Please note, the balloon will not float with helium when inflated to the minimum filling size (130mm), but will float with helium when filled to the maximum filling size (230mm). The balloon should be inflated with a slow inflating speed, such as a hand pump or mini blower.

Instructions on inflation - https://www.youtube.com/watch?v=bqCgyyOVV4k&feature=youtu.be