The DeathAdder V2 no longer uses mechanical switches for its buttons -- instead, it uses infrared light beams to register clicks. Razer says that this eliminates the risk of accidental double clicks and can even cut down on lag (though it would likely be an imperceptible improvement). Razer previously used optical switches in its Viper mouse, which was released last summer and was well-received by reviewers and gamers.
The company also announced an update to its Basilisk mouse. It uses the same internals as the DeathAdder V2, but has more buttons, which can be customized via Razer's app. The Basilisk V1 was pretty ugly, but the V2 looks much more refined thanks to its angular design and glossy accents.
The DeathAdder V2 costs $69.99 -- the same as the V1's original MSRP. The Basilisk V2, meanwhile, is getting a $10 price hike up to $79.99. They're both available now, but if you aren't opposed to settling for last year's model, Amazon is selling the DeathAdder V1 for $25 and the Basilisk V1 for $40.