1- Hold firmly the main metallic part and puch the pin until the end of it (Picture A)
2- Use the other hand to inflate repeatedly squashing the black rubber part of the inflator. (Picture B)
3-Pull out the inflator using the metallic part WITHOUT pulling the clack rubber part of the inflator (Picture C)
N.B.- During the inflating process the metallic part must be always held in your hand pushing directly to the gym ball.
Recommended for precision inflations of professional gym balls.