Drain King #750 Plumbing Water Test Fitting, (for plumbing ABS water test after rough-in for inspection). Unclogs Drain Pipes, for 3"-6" dia pipes. I purchased 4 (four) of these and never took them out of the wrapper, $15 US dollars each. See the photos instructions as to understand how it works. Call or Text: 4 two 5- six 9 eight- 9 seven 2 eight.