Review on 3 Pack Drilled Rubber Stopper 10 by Nagasree Monee

I've been looking for something to help me grow yeast and this will definitely fit my needs. I received three #10 rubber stoppers and a collapsible funnel. A neatly drilled hole runs through the center of each plug, allowing gas or liquid to escape from the bulb. Instructions for use: Insert the narrow end of the stopper into the neck of the bottle to close the opening. Optional: Insert an appropriately sized airlock, tube, or other device into the drilled hole to control the flow of gas or liquid out of the flask. Unlike the photo, my funnel was green. I assume this works the same as the red funnel.