This skimmer suction strainer is used on the suction end of a suction hose to help prevent debris from being sucked into your pump. It is a critical component as it can help prevent your suction pump from being damaged or clogged. This suction strainer has round holes on the top. It is made of zinc plated, cold rolled steel for extra durability. It has a female NPT thread and will connect to a the male NPT nipple on your suction hose. Gloxco Suction strainers are meant to be attached to the submersed end of a suction hose and is used to keep debris from entering your suction hose and pump.