1.Also Compatible with Hayward Dyna-Skim and Auto-Skim Skimmer Models SP1091ES, SP10852OM, SP10841R. 2.Dirty water enters through the water valve, passes through the filter layer, the impurities will filtered out, and clean water enters the central pipe through the pivot lateral, and finally returns to the pool. 3.Easy installation: Just remove the broken or old center pipe and install the new center pipe in its original position. 4.Please confirm whether the model is suitable before buying. SX164DA Lateral Assembly with Center Pipe Compatible with Hayward Pro Series Sand Filter Models S164T, S166T.Also Compatible with Hayward Dyna-Skim and Auto-Skim Skimmer Models SP1091ES, SP10852OM, SP10841R.