A filter's efficiency is a measure of a filter's effectiveness. In gases the particle size removed is constant but the retention efficiency varies. In liquids the retention efficiency is constant but the micron level varies. The grades we offer are-
| Grade | 30 | 40 | 50 | 60 | 70 | 80 | |
| Gases | % of 0.1um particles | 99.99998% | 99.9999% | 99.99% | 99.5% | 95% | 75% |
| Liquids | 98% of particle size | 0.3um | 0.9um | 2um | 8um | 25um | 75u |
Efficiency data should be used as a guide to filter selection. The efficiency should always be looked at in conjunction with information of the pressure drop vs. flow rates.