I like them, but would be better if they'd have 2 orings and not one. I have another POM DT with similar airflow and 2 o-rings (sku follows).
I will try to drill this one bit, but have not found one with better airflow so far (in pom with around that length).
edit:
SKU 2240000
Edited on 8/3/2015 at 1:51 AM. Reason: