Most of the Yamuna balls come deflated and you will need a pump to use them. Yamuna has specially designed a pump that is small and powerful enough to inflate the YBR balls. This pump is small, light and perfect for travel. It comes with a removable needle, so you can also deflate your balls.
Please note: Most needle type sport pumps (used for sport balls and bicycle tires) will fit into the nozzle but since they aren't specifically made to work w Yamuna balls there could be a risk for damage.