Not a CB-70 tub on the rat boxes...I'm pretty sure it's an Iris as well, but can't remember off the top of my head.

The funnel fits over the back of the food hopper - the little metal tabs on the funnel slide over the back hopper "wall" (this is all done @ the back of the rack). This will place the front of the funnel inside the food hopper, so that the food goes in w/o spilling all over the place.

HTH!

K~