Schedule 80 PVC unions are used to prepare or connect a PVC line. Unions are good in the PVC industry because they will allow for maintenance on the line without having to cut any of the line out. Unions are manufactured with socket and threaded ends. Unions are very sturdy and meet all PSI standards set forth by the PVC industry. Schedule 80 PVC unions are dark gray PVC and can handle temperatures that reach upwards of 140 degrees Fahrenheit.