First time I've ever seen this. I guess when you think about it, it's a clever idea, placing the filter right where the oil is stored and easy to change right next to the drain plug. And I use the term, easy, with sarcasm. Removing the drain plug does not drain the filter. When you unscrew the filter cap you get a good drenching of oil. Then when you pull out the filter, with pliers, you get a second drenching of oil as does the pliers.