What are the beta ratios?

Why are Royal Purple Extended Life Oil Filters constructed with a silicone anti-drain back valve?
August 17, 2018
What viscosity is recommend for motorcycles?
August 17, 2018
Average beta rating based on ISO 4548-12 multi-pass test methods: B100 = 25 (at 25 or greater micron, media is 99% efficient.) B75 = 20 (at 20 or greater micron, media is 98.7% efficient. Also considered absolute rating.) B5 = 10 (at 10 micron or greater, media is 80% efficient.)
Category: Oil Filter