| CPC E03C 1/232 (2013.01) [E03C 1/2302 (2013.01)] | 11 Claims |

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1. An improved drain assembly of a type having a drain pipe with a longitudinal cylinder containing a lower unthreaded portion, a middle portion with exterior threads, and an upper unthreaded portion terminating with a flange, said longitudinal cylinder having a selected first wall thickness, the improvement consisting of:
said longitudinal cylinder including at least one thinner sidewall portion having a second wall thickness defining a knock-out blank having an exterior blank surface recessed inward compared to an exterior surface of said longitudinal cylinder, and a peripheral groove around said knock-out blank having a third wall thickness thinner than said knock-out blank providing for easy breakage and removal of said knock-out blank; and
a resilient removable knock-out band for covering a knock-out overflow aperture formed from removing said knock-out blank providing a removable water tight seal.
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