This Waterway square spa skimmer is supplied with a basket for catching leaves, among other things, and must be connected to an external filter.

It has a socket to connect to 2" or 1 ½" pipe. 

For a 1 ½" connection, glue the pipe directly into the fitting on the base of the skimmer. 

For a 2" connection, you would need to glue an elbow or straight connector onto the skimmer fitting.

We also stock a slightly larger skimmer from Waterway, equipped with an integrated filter cartridge in addition to the basket.