Product review (4 stars): Model DD-HEMT120 Hose End Mech. Timer
I bought two of these timers through Amazon in June of 2012. As of this writing I would have to say that the first one has failed. In the past few days, water has started to run out from under the timer knob when the timer valve is open. It always leaked some at the faucet connection. I put the second one into service today. I will update this review if there is a substantial change in the way that the second valve performs. The following might apply to any mechanical hose-end timer: I will be placing an anti-hammer device between my faucet and this timer. When the timer's valve closes I can hear it in the pipes throughout my house.
Addendum Jun 7, 2014: I have been using the second timer from this purchase for about 9 months. It is working just fine.
If I can, with the edit of this product review, I'm going to change my rating from 2-Stars to 4-Stars.
I did add an anti-hammer device between my hose bib and this timer. My water pipes are quite now; I have to use a timer to know when to move the hose.