BB has these for $14.99, which is about $5 lower than similar-featured comparable value product on Amazon. The Amazon ones clamp (pop) at 600v. These ones clamp lower at 500v. My understanding is that ideal is somewhere around 300.
So, not for use with super-sensitive electronics (you'd probably have a separate surge protector on those anyway, TBH), but still a nice no-thought surge protection on most devices without breaking the bank. We have highly variable power in our neighborhood, and these will be replacing a number of our outlets that have already fried.