This perk fits all the either pieces just fine but the air flow was not good on mine and would drain water to the lower one after hitting it
Thank you for your purchase from 420 Science. I'm sorry to hear that your STAX Halo Perc is not working correctly, you should definitely fill out a defect report at http://www.grav.com/defect-report/ and GRAV should be able to get you taken care of.
Make sure if you don't hear back from them after a day or two that you check your spam/junk mail folder as their messages may have been automatically redirected.
If you have any other questions or concerns, please don't hesitate to ask.
Perfectly Designed with excellent airflow. Cant wait to collect them all