The FC5633 Rubber Coupling Flexible Connector - 3" x 3" is a type of flexible pipe coupling used for joining non-pressure drain, waste, and vent (DWV) piping systems. A widely available and prominent equivalent is the Fernco 1056-33 or ProSource FC56-33. 
Key Features and Specifications
Size: 3 inches x 3 inches (nominal). The internal diameter is designed to fit pipe O.D.s (outside diameters) ranging generally from 3.10" to 3.70".
Material: Constructed from durable, elastomeric polyvinyl chloride (PVC) with corrosion-resistant 300 series stainless steel clamps.
Pipe Compatibility: Suitable for connecting a variety of pipe materials including plastic (PVC, ABS), cast iron, copper, steel, or lead pipes.
Applications: Primarily used for sewer, drain, waste, and vent piping applications, both above and below ground. It is not intended for pressurized plumbing systems.
Pressure Rating: Maximum test pressure of 4.3 PSI (29.6 KPA).
Temperature Range: Suitable for temperatures from -30°F to 140°F (-30ºC to 60ºC).
Resistance: The coupling is leak-proof, root-proof, and resistant to chemicals, UV rays, fungus growth, and sewer gases.
Installation: Easy to install using a screwdriver or torque wrench; no special tools, primer, or glue are required.
Certifications: Conforms to industry standards such as ASTM C1173, ASTM D5926, CSA B602, and is UPC approved.