Stainless Steel with double-wall vacuum. 

Lids are clear with the plug color matching the handle color. 
Version 2 has Opaque Tops with matching stripe on top and handle. (Black has Black Top)

Approx Stainless Time / Temp: 400 degrees for 2 minutes

NOTE: Suggested Times/Temps are for mug / stainless presses. We cannot provide or support time/temp for air fryers or conventional ovens.