Sioux Chief Mfg 660-2 1/2-Inch MIP Thread Mini Rester Residential Water Hammer Arrester

After we installed our sprinkler system, we found that every time a valve shut off, the pipes would rattle and bang for several seconds. This went on for years until one night, I was awakened by loud clatter only find that the pipes were rattling and not stopping. I finally stopped the rattling by opening a hose valve and slowly shutting it off. I found and bought this little item from Amazon after researching the causes of "water hammer" and the possible cures. It was very inexpensive and after receiving it just a few days after ordering, I installed the device into a Tee section near the sprinkler valves. We allowed the sprinklers to come on and go off as usual and it worked perfectly. Not a sound! Even if you don't have rattling pipes, this is well worth installing as a preventive measure to protect your pipes.

Worked well, just a little undersized for a standard water bib and timer. Its built like a tank and is easy to install, just wasnt powerful enough for what I needed. Unless you need to put it in a small space I would recommend the larger version. After trying this one I added the bigger one and they work great together.

UPDATE 3/23/18:I've had 10 of these hammer arrestors installed in my house for almost 3 years now. Not one of them has failed and they all still eliminate any trace of water hammer. Very happy with the investment I made on them.ORIGINAL:Absolutely eliminated water hammer from my house. I am on a raised foundation and every time the toilets stop filling or the sinks are shut off, the pipes under the house sound like bombs going off.I installed one of these on each toilet and under each sink (hot and cold) and the hammering has completely stopped. I listen carefully and can't hear anything coming from them now.I like these because they can be installed/removed from a "T" fitting without disconnecting the hoses.Just keep in mind you'll have to buy a separate brass "T" fitting to install on toilets/sinks.

I miss read the description and ended up with a MIP threaded connection but needed compression connection. When I went to return the unopened package I was told the it was not eligible for a return. First time I’ve encountered this with Amazon. Very disappointed!!

Used in combination with  SharkBite U3482LFA Slip Tee, 1/2-Inch by 1/2-Inch by 1/2-Inch , I was able to tee into my 2 existing copper shower pipes and install in about 10 minutes each. Make sure to use a proper pipe cutter to get a square cut (I used  Ridgid 32975 1/8-Inch to 5/8-Inch Close Quarters Tubing Cutter , deburr the ends (I used  Cash Acme U702A Shark Bite Deburring and Depth Tool  (this also allows you to measure the depth of the pipe for the Sharkbite fitting if you're using one), and use a bit of teflon thread tape when attaching the arrester to the tee fitting.Worked perfectly and significantly reduced the hammer noise instantly. Will report back with any problems, but am very happy so far.

I received mine just last week and it is not copper as shown in photo and as indicated in the photo. I dont know what it is made of.So I tried to initiate a return because of this and I was not allowed.UPDATE: Amazon is going to refund my money after I emailed my concerns. Hopefully the website description will be updated so customers have a better understanding of what they are buying.

I had a sprinkler manifold that I installed full bore 3/4" anti siphon valves on and the water thudding was waking me up it was so bad. I installed it in line in the direction between the valves to the water main directly on the manifold. It worked like a dream to stop the water hammer. I can't even hear it shift from valve to valve if I try. I was surprised such a little device solved such a large problem. My water pressure and volume is significant since I re-piped my entire house to the meter with 1" copper. Great product!

Failed after 2 weeks. Now I’m buying something else to replace.