The reason I rated it 4 stars is that I am using it on a 10 gal rubbermaid cooler. Looking at the answered questions I thought it was the right product.
First the rubbermaid coolers work with 3/8" npt, For 1/2" you need to drill the hole larger.
Second the Nipple that comes with the one I received has Hex style and is too short to fit, Thus it needed to be replaced. Also additional 7/8" washers where needed, placed between the valver and the outside of the cooler.to get a good seal.
About $10 in extra parts and drilling of the cooler
On my first Conversion of a 5 gal cooler, I used a 3/8" valve and nipple. This allows the use of the original rubber washer and requires no drilling. This is really the way to go; Overall I paid about $20 less, easier mod and works just as well.

The Manufacture deserves 5 stars as they do not make any claims that this will work on a cooler.

I replaced the ball valve on my 10 gal cooler. It's working fine without leaks and the lever action is smooth enough. The one I received is a full port valve.

I was hoping for a 3/8" barb like the picture shows but it was a 1/2" barb instead.

The kit doesn't use a close nipple, so there is little room for fittings. I need a F-F coupler inside for my false bottom so I put the locknut and small o-ring aside and did the following:

Wrap both NPT thread ends with teflon tape. Put the big washer on one end and feed that end into the cooler from the outside. Put the large o-ring over the nipple on the inside and then attach your coupler. I used a thin film of silicone o-ring lube on the end of the coupler so it would not deform when tightening. Hand tighten. Then attach the ball valve to the outside end of the nipple and hand tighten. I put vise grip pliers on the coupler to help hold it while tightening the valve up. You can use a swatch of cloth rag or leather to help the pliers hang onto the coupler. The assembly will still be able to rotate along the long axis, this is normal. The large washer gives it stability for operating the valve lever..

I'm still undecided on the locking mechanism but it can be removed if needed.

Happy mashing!

This product works just great, but there are some things that you need to be aware in order to utilize it properly in the construction of a homebrewing mash tun. As pictured is precisely how it is delivered. This item, in my opinion, is absolutely perfect for a hot lauter tun or brew kettle that you intend to add a weldless spigot to, without any further connections.

If, however, you plan to use this in the assembly of a cooler mash tun build, realize that there will not be anything left to connect to on the inside of the Mash tun. The included washers and gaskets will provide a remarkable seal, however there will be no threading left to connect a false bottom adapter to. I had to forgoe a nut and gasket in order to have enough threading available to attach my false bottom adapter, but was still able to achieve a leak free installation.

The threading on this, by the way, is male NPT threading. If you're placing this in a bulkhead, perfect. If not, know that you will likely have to switch out the NPT adapter on the Amazon suggeted false bottom adapter hose to a female one for these male threads to go into. Giggity.

My daughter is in to making candles and wanted a pot with a spigot on pour wax. She as able to find them online but could not afford one. So, I purchased this spigot and a pot of her choice and was able to produce the pot for $100 less than the online prices.

This is a stainless steel spigot with a safety lock built into it at a price lower than the big box stores. I saved money Sarah is happy and life is good.

I mounted this product into a 10gal igloo cooler, using the stock spout hole.
https://www.amazon.com/Igloo-Gallon-Beverage-dispenser-Dispenser/dp/B000F6SHTK/ref=sr_1_1?ie=UTF8&qid=1493860503&sr=8-1&keywords=10+gallon+igloo+cooler

The washer that goes on the outside of the cooler (the large one shown on the right side of the picture next to the large nut) had to have the inside ground out a touch to make it sit on the shoulder of the NPT nipple rather than on the last turn of the thread, but no big deal. That was really needed to get the last 1/16" of depth I needed to fit that cooler.

For the cooler, I also had to put the large gasket as well as one of the small gaskets together on the inside of the cooler, as well as pipe tape on the threads to get it to seal up completely. I imagine if this was being mounted into a metal wall it would probably be a little different.