Product review (4 stars): Good protection against accidental burns.
These guards work pretty well; they take a little getting used to, and they roll around on the rack edge a bit.  But I am a klutz and was constantly burning the tops of my hands, so these serve me well in two ways - they are bright red so I am always aware of the hot rack edge, and they do provide enough protection that an accidental touch isn't burnt.  (Note: They are NOT meant to be used without also using an oven mitt or something else to protect against high heat if sliding the racks or hot dishes in/out of the oven.)  I do wish they were as long as my rack width, but I can fix that - I am buying a second set and will cut them to provide full protection across the edges of all my oven racks.