This product was a complete disappointment to me. As a new buyer, I was expecting a durable and efficient large rubber grommet but instead, I received a flimsy and ineffective one .Industrial and SCIENTIFIC? I think not. As a result of my tests, I determined that this grommet just wasn't worth the investment. The only pro is that it was easy to install, but that was outweighed by the cons of its poor quality and performance. Save your money and look elsewhere for a better product..