Product review (3 stars): Its the factory part at the lowest cost...
This is a replacement timer for a number of Whirlpool-based and manufactured dryers, such as Kenmore. The Amazon price and delivery are better than any of the typical appliance parts online and internet retailers; I paid less than $85 here, and the typical price at the other places was $107-$114.  While the original dryer timer (my dryer is from 1996) lasted 15 years or so, the replacements have lasted just a few years each. All the replacements are the same Whirlpool part regardless as to whether branded as Whirlpool, FSP, or Kenmore. This is the third replacement now. The timer's box says made in Mexico, but the timer itself says Assembled in the USA, and the motor is stamped China. I'm projecting forward that this will last just as the others did, a few years, thus the three stars. BUT, you won't find it any better, so don't bother!  Now, for installation: if you see all the installation videos, they make it seem super easy: remove the knob, remove a few screws from the back panel, remove two screws from the timer, swap in the new one. Well, they are NOT all that easy. My Kenmore has a back that is far more complex. There are just a couple of screws holding it on to the base, then some weird plastic things that hold it to the sides, but here's the kicker: there are THREE screws, INSIDE, holding it to the base. See the photos. Once the EXTERNAL screws are removed, you'll have to bend back the top a bit, insert a 1/4" socket on at least a 6" extension in order to reach these. So, if you remove all the screws from your back and it's not budging, then you may have hidden screws. Knowing that this part crosses to dozens of models, across several brands, my guess is there are more mysterious ones out there besides mine. BTW, the symptom of my timer failures has all been the same: the timer keeps going after a cycle, thus the dryer will restart on its own.  One thing I did notice is that when I pulled the "defective" timer off and had both the "new" and "defective" in my hand, the defective timer clearly had something rattling inside. I also notice that the timer's motor is removable, so  after removing, I've identified that the rattle is inside the motor. I'm going to try and find a replacement.