We first reviewed a Corsair K70 keyboard back in 2013, and it's still a great, reliable mechanical board seven years later. This isn't exactly the same keyboard—it's actually a slimmer low profile variant with Cherry MX Speed Switches, which are linear switches like Reds or Blacks but with an even faster actuation. The idea is Speed Silvers are meant to make your reactions just a little bit faster.
The previous lowest price we've seen this keyboard go for is $100, so this Best Buy deal is a good one. It shaves another $10 off that price. And unlike some of Corsair's budget mech variants, this one still has full RGB backlighting.
This K70 deal from Best Buy is part of its "Black Friday Prices Guaranteed" sale, where anything discounted today is guaranteed to be as cheap as it is on Black Friday in November. If it ends up going for less next month, Best Buy will pay you the difference (though of course, you should read the fine print).
This is Best Buy's alternative to Prime Day sales. You can find our coverage of all the deals Amazon has to offer, plus a few from retailers like Best Buy and Newegg, over at our Amazon Prime Day deals hub.