Which one? They vary ...although I'll say that in the filters that I've looked up, 19um appears to be the nominal value of high frequency.
Part Number: 51515
UPC Number: 765809515154
Principal Application: Chrysler Family of Cars/Trucks (57-70), Ford Family of Cars/Trucks (57-00), Mazda Trucks (94-00), Toyota Landcruiser (71-96) - (Two Quart version is 51773)
All Applications
Style: Spin-On Lube Filter
Service: Lube
Type: Full Flow
Media: Paper
Height: 5.178
Outer Diameter: 3.660
Thread Size: 3/4-16
By-Pass Valve Setting-PSI: 8-11
Anti-Drain Back Valve: Yes
Beta Ratio: 2/20=19/41
Burst Pressure-PSI: 270
Max Flow Rate: 7-9 GPM
Nominal Micro Rating:
19
Part Number: 51348
UPC Number: 765809513488
Principal Application: Various Chrysler/Jeep (82-06), Various GM (85-05), Lexus (90-06), Saab (67-06), Saturn (91-01), Suzuki (86-02), Toyota (88-06), Yugo (86-89), Harley-Davidson, Various Lawn&Garden, Farm Equip.
All Applications
Style: Spin-On Lube Filter
Service: Lube
Type: Full Flow
Media: Paper
Height: 3.404
Outer Diameter Top: 2.921
Outer Diameter Bottom: Closed
Thread Size: 3/4-16
By-Pass Valve Setting-PSI: 8-11
Anti-Drain Back Valve: Yes
Beta Ratio: 2/20=21/37
Burst Pressure-PSI: 275
Max Flow Rate: 7-9 GPM
Nominal Micro Rating:
19
Keep in mind that the listed nominal (in bold) at times disagrees with the statistical nominal (beta ratio) figure. In the above example ..the nominal (50%) is rated at 21um (Beta21=2 2=1/2=50% or 50% of the 21um particles are removed in their test and 19/20th = 95% of the 37um particles are removed.
So take this FWIW
You can find this data by entering the filter number of choice at
Wix You can enter any filter number and it will puke out the above data if they make an equivalent.