Most important, the filter wrench is steel and fits the listed Subaru OEM oil filter perfectly. Might be just me, however, with all metal filter wrenches I've used, the square hole should be designed to be a half inch higher on the wrench so an extension can be inserted "fully" into the 3/8" square hole. If I put the extension all the way in, the wrench cannot fit flush on the oil filter. I have to put the extension in "loose" so the wrench fits flush on the oil filter for maximum grip. It's minor, but I rather have the extension solidly connected. Still, I like this filter wrench.