I have them on my trucks and we have installed several for customers. They are working very well and we have the oil sample tests to show the results.
The Premo is a 3 micron absolute by pass filter with an evaporative head to remove liquid contaminates. With clean oil and the contaminates removed the additive package in the oil will last much longer. With the Premo change the Premo filter every 20,000-30,000 miles and don't change the oil. Anyone who would like more information about the Premo and a CD with information about filter ratings and how the Premo works, please contact me and I will be glad to mail you a package.