Again FYI, don't shoot the messenger. From the Purolator website. A history lesson.
Over the years, Purolator was first with many other oil filtration innovations.
The First "Full Flow" Filtration System - Prior to 1943 oil filters only filtered about 10 percent of the oil flowing through the engine. This system was called a bypass system. However, during 1943 Purolator developed the first "Full Flow" filter that was capable of filtering 100 percent of the engine's motor oil. This led to the Full Flow lubrication system that is in use on today's automobiles.
Micronic Paper Filter Element - Three years later, in 1946, Purolator, in association with Chrysler Corporation, patented the first "pleated paper" oil filter. This is a technology that is still being used in the construction of oil filters today. Prior to this time, the filter's media was made from a cotton waste material.
First Block-Mounted Oil Filter - In 1948, Purolator developed the first Original Equipment "block mounted" oil filter. This was an important milestone in the filter industry because now the oil filter had become a standard part of the automobile engine. Earlier oil filters were typically mounted on the firewall somewhere underneath the hood of the vehicle.
First Spin-On Oil Filter - It was also Purolator who developed the first "spin-on" oil filter in 1955. Earlier filters were of the cartridge type design that had to be placed into some type of housing or canister.
In the 1960's and 70's Purolator developed filtration products for:
Transmission Fluids
Power Steering Fluids
Hydraulics
Coolants
Crankcase Emissions, and other liquids and gasses