70-200mm f/4.0 L IS tripod collar?

Just wondering if there is a tripod collar accessory for this lens? If yes, is it available for purchase now and where?

I currently have a 70-200mm f/2.8 L IS lens w/tripod collar. Would I be able to use the collar on the f/4.0? Im guessing the 2 lens are different size so the collar wont fit properly.

Thanks!