The ESS Air Sampling Bag incorporates a two opening system for sampling and extraction.
The side port/stem (3/16” OD) allows filling with a pneumatic pump and tubing, and for rapid emptying of the bag.
The top of the valve is turned clockwise to close and counter clockwise to open. Continually counter clockwise turning will lead to the top of the valve coming off. One full turn is sufficient to fill the bag.
The hole in the top of the valve allows you to inject or extract through a septum with a syringe.