Zodiac Polaris 6-500-00 Universal Wall Fitting, White. (Fits 180, 280, 280 Tank Trax, 360, 380, 3900 Sport and 480 Pro Automatic Pool Cleaners.) This is the collar that attaches the Polaris Universal Wall Fitting into the wall. One side has 1-1/2" threads that goes into the pool wall, the other side has the 2 nubs that the bayonet fitting locks into to.