Air Filter Cover
Nice, ya that Losi filter is so convenient especially with the pre oiled filters. I do it the same way you do, but with the Hi-Flow (Fluorescent Green) racing ebay outer covers. I keep motors all year, and never lose them to dirt, its a great combo. I also run the standard ebay outer cover during practice, to really cut down on filter maintenance during the week.
Try them if you haven't...