Product review (5 stars): Fixed my water dispenser constant dripping for less than the cost of a service call
Too bad I didn't learn about this a few years ago.  This part was the reason my KitchenAid/Whirlpool refrigerator's water dispenser leaked constantly.  The problem started several years ago.  We'd get a glass of water & instead of cutting off the flow of water promptly, the water dispenser would keep dripping.  At first it was just a drop or two, but gradually the problem got so bad I finally turned the ice maker off and turned off the water supply at the wall.
Thankfully, our appliances have been very good.  We've had about 5 appliance service calls in the past 20 years. The only down-side of that is that I don't have a repair service I know I can trust.  So each time I try someone out, I swing a dead cat around my head 3 times after soaking it in stump water.
This time I went to the Whirlpool web site, downloaded the parts manual for my fridge and started checking into the cost of buying parts.  That way at least I'd know whether the repair man's price was reasonable.  I scheduled a service call.  But I kept looking into this parts situation online, and somehow got a brain-wave: try Amazon!  Sure enough, as I looked at the various water system parts, I found that this sucker was probably the cause of my water dispenser leak.
I canceled the service call, bought the part, looked at "Steve's" video on how to replace it on YouTube (find it by part number), and did the job myself for less than the price of a basic service call (To be fair, the service technician would've applied the service call fee to the repair).  It took me about 40 minutes to complete the job.  One of the supply hoses was too short to bring the part out from under the fridge.  I traced that hose to the back of the fridge and saw a place where I could unscrew it by hand (a plastic fitting with ridges).  I replaced the part, hooked the hose back up, then started running a bunch of water through the dispenser to get all the air bubbles out.  As I did that, I noticed the sound of water squirting out of one of the connections I had just made, so I pushed the hose in a little harder; that did the trick.  After clearing all the air bubbles out (takes several gallons of water), the job was done.  Just 1 or 2 air bubbles in the line will make the dispenser drip.