The new Grip Tip Test Cap from Sioux Chief is a cost-effective solution for end cap and test plug users. The new test cap glues over the end of DWV pipe to create a solid seal for testing. Like the original Grip Tip, the new cap has the same dual tip design that allows the DWV system to be air or water tested. The Grip Tip replaces cheap caps and plugs that break into pieces and are difficult to glue. Sioux Chief Mfg. Co.