You are purchasing 1 New Gray Water Outlet Screen Fitting that will work for a  16' x 48", 18' x 48", 20' x 48", 18' x 52", 22' x 52", 24' x 52", 26' x 52"  Coleman or Bestway pool. 

Manufacturer's Part Number is P6680

Diameter of hose attachment is very close to 1 inch in diameter.