It is advertised for medium, medium-hvy and hvy oil, but it doesn't work on those conditions. At least not in my area. Here it is good for medium-light and medium only. The Ace has a little bit of a stronger backend than the Extreme, but the Extreme will successfully handle more oil than the Ace. Anyhow it does where I live and bowl.
--------------------
Why do you need my signature?....You know who I am.