This is the inferior BioQuip pooter I had used exclusively prior to making my own. It had a screwy design that I improved on by adding a length of vinyl tubing to its very uncomfortable "mouthpiece," a bent aluminum tube. The BioQuip design has a small bit of fine-mesh stainless steel screen on the bottom end of the mouthpiece that keeps insects out of your mouth. I used a small piece of sheer curtain fabric on mine.
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