"Frantz" was the most popular brand. My dad, who had been a traveling salesman all of his life, selling fuel and supplies for Municipal Generating plants, was a rep for Frantz after he retired. The thing I remember about them is that they came with a sticker, about the size of the old oil change stickers that they used to put on the door jambs, except it was made of blotter paper. You were supposed to take out your dipstick every 100 miles after you installed the filter and touch it to the blotter sticker. After you had done this (I think the sticker had 5 "boxes"), and the oil "dried", you could actually see it get cleaner and cleaner, so that part of it actually worked. We had them on our family cars, my dad's '58 Olds Super 88 and my mother's '58 Nomad. The cars retained their factory full flow filters and we considered this a "belt and suspenders" approach, and still followed the recommended oil and filter change intervals. They really did clean up the oil.