I meant concentrate, my mind is broken due to a cold and for some reason I'm not seeing an edit pathway on the mobile app I'm trying. Apologies.

That makes sense. The mug version of Ember (https://ember.com/products/ember-mug-2) is open on top, which seems like a fancy Bluetooth version of an old-school mug heater.

I could see the sealed one (the "Cup") as working better though.