The Logitech MX Master series is about as good as high-quality mice get, as long as you don’t need a gaming-specific model. Today, Lenovo’s online store is selling the MX Master 2S for just $50 with a coupon code. This model is a few years old, but it’s still rare to see a new version going for less than about $70. It’s a fantastic deal. The MX Master 2S features a sculpted body with premium materials, a super-fast ball bearing metal scroll wheel, and customizable thumb buttons with a second horizontal scroll. Its 4,000 DPI “Darkfield” sensor works on just about any surface, including glass. (…