The holes at the top are for the antivortex baffle to mount, which will center the outer pipe on the top of the 8" by the way it is notched on the underside. The ring of holes around the bottom are for 3" long 1/4" fully threaded SS bolts, which will have the head on the outside of the pipe, and a nylock nut on the inside to hold them in place. The end will press into the side of my 8"-6" reducer which will hold the bottom of the pipe centered and lock it into place. The bottom ring of bolts will also act as a coarse screen to keep things from getting between the two pipes. The openings are roughly 1.5"X2". I have all the parts needed to finish, I am just lacking the time. I will post pictures when done.