The new heat sink, equipped with a Makrolon stem, was made with customer feedback in mind. Some reported a scratching noise that was made when pulling up and down on the mouthpiece. That noise was created by the glass material making contact with the ceramic inner sleeve. Please note, no glass was eroding from the mouthpiece. 

Research shows Makrolon is a far more durable material than glass. We found that the glass material did not allow for consistent performance.

You'll notice the Makrolon stem fits loosely. This is normal. What we found was happening with the previous design was when customers were pulling up on the mouthpiece to re-position it, the resistance was causing the lid of the heat sink body to become detached, unknowingly causing a bypass. This was causing performance issues that were understandably undetected by the naked eye.

Overall, the benefits of the redesign is a perfect seal, a more durable mouthpiece, and consistent performance. Should you have concerns about the seal with your heat sink, we encourage you to carry out the air bypass test on your heat sink. For your convenience, here are written instructions:

* Remove the heat sink

* Place heatsink in the palm of your hand, blocking the holes on the bottom.

* Please make sure the holes are covered, or the test is inaccurate.

* Extend the stem, and try to draw air (sucking in).

* You should not be able to draw any air through the stem