505....I hope you can take criticism, because I'm not trying to offend you by the following statement. I don't think it was a good deal at all, but that's what cousin's are good for, right? The rock is a mixed bag of all kinds of stuff. I see Indo. rock, tonga, even looks like some homemade stuff in there, but none of it is very attractive. It will all work fine for base rock as long as you get rid of the aptasia and hide this rock under some better display pieces.