Fall has arrived, bringing cooler temperatures with it. Thankfully, Ember is running a sale through October 21st that takes 20 percent off many of its self-heating vessels — including the Ember Mug 2, a guilty pleasure of ours. The 10-ounce mug is available for about $104 ($27 off) with promo code SEASON20, while the 14-ounce version is down to about $120 ($30 off). The same code is good for the metallic versions of either model, too, as well as the 16-ounce Ember Tumbler (now $143.96) and the ultra-fancy Travel Mug 2 Plus (now $159.96).

Each Ember Mug 2 features a built-in battery, which allows the second-gen smart mug to last up to 90 minutes per charge or indefinitely if you set it on the included charging coaster. It pairs with a barebones mobile app for Android and iOS, as do the like-minded Ember Tumbler and Travel Mug 2 Plus, letting you lock in a temperature between 120 and 145 degrees Fahrenheit. The 12-ounce Travel Mug 2 Plus takes things a step further with LED status lights, onboard controls, and support for Apple’s Find My tool, giving you an easy way to keep tabs on it using an iPhone or Mac.

It’s worth noting that Amazon is selling the Mug 2 in some colors for even less right now — a 10-ounce mug can be had for as little as $87.99 — but Ember’s current promo is the only way to get a steep discount on the new purple option (and several other colors). Those prices are still pretty high for drinkware, but they’re a nice way to keep your cup of joe, cocoa, and other warm drinks at the proper temperature — that is, without having to constantly nuke them in the microwave.