www.phcppros.com/articles/7361-jones-stephens-drain-test-plug

Jones Stephens Drain Test Plug
April 24, 2018
The new disposable test plug fits an existing line of residential shower drains. This test plug enables code-required pressure testing of the drain-waste-vent system and wet testing of the shower liner membrane without the need of a separate testing device.
The preinstalled plug is secured in place by the spud during construction and testing. Once all testing is complete and the finishing touches are being placed on the bathroom, the plug is easily removed with pliers and discarded.
Jones Stephens