Connectors (Cross) made of polypropylene (PP) are laboratory fittings used for connecting and directing the flow of liquids or gases in laboratory systems. Cross connectors have four separate paths for fluid or gas flow and provide a way to split a single stream into multiple streams or to join multiple streams into a single stream.

The connectors are designed with barbed or threaded connections that can be used to secure hoses, tubes, or other laboratory fittings. The use of a PP material makes the connectors durable, lightweight, and resistant to chemicals commonly used in the laboratory.

Additionally, polypropylene is chemically resistant and can be used with a wide range of liquids or gases without risk of contamination or corrosion.