Product review (5 stars): Great llitte coupling
For years I had one of these on the drain hose from my washer to the standing drain pipe  in my laundry.  A few years ago I bought a new washer which was delivered and installed while I was at work.  The coupling was missing and when I asked about it, no one knew a thing about it.  Oh well.  I tell that story because I wasn't able to find once of these locally and so I simply have had the hose sticking loose into pipe ever since, which mean I don't really need one.  I found this on-line while looking for something else and so I ordered it.  It is nice that Amazon has a program where you can bundle low cost items and qualify for free shipping,  Without that I wouldn't have bought this.

OK, enough of the irrelevant stuff.  This makes a very tidy, secured and sealed connection and there is nothing to the installation.  I am happy to recommend it for this reason alone.  It also pretty much eliminates the possibility of the drain hose inadvertently being pulled out of the pipe and the resultant flooding the next time the laundry is run.

After I posting this, I saw the only other reviewer mentioned that his installation was made because his drain did not have a gas trap.  I am not a plumber, and so will confess I don't know if there is anything to be concerned about, but I am not sure that this coupler is meant to eliminate the need for a gas trap.  If sewer gas is escaping, can't it come right pass the connection and enter the house through the machine?