It's there to protect the original 510 threads. After reading another user's experience with their 510 threads stripping, a 2 dollar extender seems like a simple and solid way to protect my investment, stripping the original threads would cost 75 dollars to replace (almost the price of the whole unit). Being sealed, it also helps protects the battery in the case of leakage since it's self contained, the shop that sold me the device warned me about being careful if cleaning the original inside of the 510 thread, applying force on that center piece going down to the battery can get pushed in or break. Was even thinking of adding a second extender, unsealed, ontop of the original if I want a more airy draw in the future while still getting the added leak-protection benefits.
Another idea I was some form of rubber gasket like part in the shape resembling a washer or screw nut that sits snut over the 510 extender, with a diameter large enough to match the
tank thats just as tall as the extender (10mm I think?), though that sounds even less likely to find or make.
Along the same lines, was also thinking maybe a spring with a shorter diameter than the top of the end cap the length of both extenders + an extra couple millimeters might look nice and provide some resistance against the bottom of the
tank tank to provide a little more support.
