In my observation, what 'I thought' most filters that say "leak tested" had in common is that they are off shore manufactured filters. Primarily but not limited to China coo. A quick search of the site shows, filters Security Global, Ecogard, ProGauge, Pronto, FVP Reliaguard, Parts Plus, and the old AAP Driveworks to name some, show leak tested on the dome. Possible some of those like Parts Plus are PG filters, but I'm skeptical they all are. So, while all PG and PG made filters may say leak tested (IDK), less sure all that do say it are PG filters. Another common feature of the China coo filters, they use a coil compression spring.