Wrist rests just raise your forearm if it's too low for you to type comfortably. Whether it works to reduce strain or not depends on the angle of your wrists before and after adding the wrist rest; which is affected by things like chair/desk/keyboard height. For minimum strain you'll want to have a setup that lets you type with your wrists either straight or with a slight downward bend. Your forearms should also be at a 90 degree or slightly downward angle and you should be able to type while resting your elbows on arm rests. You'll also want to rest your wrists on the head/styloid process of the ulna and not on the center of your wrists where you can compress nerves.
As for this wrist rest, if you don't mind the goofy looking duck head, this is an OK price for that type of wrist rest if you don't want to deal with importing one from China, though you can choose from a large variety of logos and colors if you choose to do so. Since the wrist rest has foam in it, the foam will break down over time and compress in the areas you rest your wrists.
