I thought this was a little expensive for a sprinkler timer, but it seemed to have the most good reviews so I figured I'd try it. It is made of all plastic. It isn't excessively heavy. If it were made of metal it would be. I opened it and plugged in a 9V battery and had the thing programmed in about 10 minutes. Not difficult if you read the directions. I had it hooked up to two sprinklers in about another 15 minutes and it was ready to go. It has been watering as instructed for three days now with no problems. I had another timer that had a valve that closed very abruptly and created a significant water hammer in the pipes in the crawlspace. Not good. This Claber timer does not cause water hammer. It has slow close valves. Here are some thoughts on this product:1. It's kind of tall. If your spicket is close to the ground, then it might be difficult to attach this to the spicket and then attach the hoses to the bottom. I had just enough clearance between the ground and the sill cock to fit in this timer. I could have always not used the plastic quick connects for an extra inch of clearance I guess.2. The quick connects are made of plastic. I have never been a fan of plastic quick connects. These are probably the highest quality plastic quick connects that I have ever seen, but I still prefer brass. It would be nice if Claber included an extra end or two to go on the hose so that you can hook in a hose with a handspray if you have two sprinkler zones set up.3. As for the time programs, you should note that it will only water three distinct time periods per zone (for a total of six). So if you wanted to run only one line six time a day, you have to rig up some sort of siamese connection to connect one hose to both outlets. I don't think this is clear enough in the product description.4. Manual mode is easy enough to engage. It automatically goes back to timer mode after 15 min (not adjustable).5. I do have some concerns about the long-term water-resistance of the housing. There's no gasket between the front and the back and it's not a super tight fit....So, to summarize: expensive, but possibly worth it. I'll report back next year on how it is holding up.In 2009, I purchased and tested several timers before settling on the Claber. Its higher cost led me to try several alternatives before going for the Claber. It would have saved some very bad experiences with cheaper products that all seemed to be designed to be cheap - to the detriment of operability,reliability, endurance, and convenience. Bu contrast, the Claber is exceptionally well designed to work flawlessly and conveniently over the long haul. Quality of design and execution is especially important in a product that combines digital, electrical, mechanical, and tap water technologies. The single 9V battery in the Claber lasted more than three years - even though my unit opens and closes both valves twice every day. The unit's attractive but sturdy plastic case (as pictured by Amazon) looks as good today as it did when new - quite an accomplishment after well over 1,000 days of outdoor use. It is out there every day except during freezes. I found it hard to program. The people who designed the unit probably find it easy, I did not. It had taken much time to program it the first time, three years ago. It took just as long now, after the new battery was installed, because there are just three buttons to program time, days of week to operate, six times of opening and closing of valves, three for each water outlet. That makes for a lot of combinations of settings. The printed manual is reasonably clear and, importantly, also available also for down-laod just in case. It describes how to use the three buttons to program all the different features. It also explains an issue that had vexed me both times I had to deal with it: it seemed impossible to use all but the first two or three of the six watering times. The reason for this is that the six watering times must be set sequentially. For example, if you programmed #2 to end late at night, say, 23:00 (military time for 11 PM), then you can program # 3, 4, 5, and 6 only for times between 11 PM and midnight. The solution is simple: program the earliest watering time on #1, the next on #2, and so forth. Is it all worth it? You bet! On a Claber, you do this once in three years, then forget about it unless you want to change something. On other units, programming may or may not be easier or quicker - but you have to do it more frequently because they do not last as long as the Claber. In sum - the Claber is the best electronic water valve I have found. Its quality, performance, and endurance make it well worth the price. I would not even consider a cheap alternative.Ottimo funzionamento ma software pessimo complesso e d'uso piuttosto difficile e poco intuitivo da usare .lo sconsiglio a chi ha difficoltà a far funzionare congegni elettronici.E' veramente molto molto difficile da programmare di una complessita veramente alta , pessimo programmatore chi ha congegnato il software.just bought this Claber 8420 and it is amazing. I love the fact that you can start one outlet for as long as you want then stop it and start the second one for as long as you want it to go. It's a big load off our shoulders. Easy to program and there is also a video that explains step by step. Now we can leave for the weekend and not worry about our vegetable garden or our flowers! I really do recommend anyone to buy this.Come detto nel titolo il prodotto venduto è il claber 8410 (8420 non esiste). Programmatore di facile installazione e programmazione. Effettua fino a 3 irrigazioni giornaliere per linea. Si può collegare il senatore pioggia Rain Sensor. Venditore gentile e disponibileEasy to program. Takes 2 irrigation pipes. Lasts many years when stored indoors in winter.Regalato a mio papà amante del giardinaggio, spettacolare, molto utile in estate e con il rilevatore di pioggia risparmio anche acqua.