Double walled items seem to be hot right now (but not to the touch!). The latest product that takes advantage of this design are the notNeutral Ciclone Tumblers. A double wall is excellent for hot or cold liquids because it helps keep the heat (or lack thereof) where it belongs. The notNeutral Ciclone Tumblers come in three sizes: 2.5 oz, 6 oz and 10 oz. We love the 10 oz. option for iced coffees (its almost summertime!). The double wall design is great for iced coffees because it eliminates the inevitable sweating glass! Each tumbler is hand blown from borosilicate glass (which is a great conversation piece), but be aware there may be slight variations from cup to cup. Borosilicate is a laboratory grade glass that is both heat and scratch resistant, so feel free to put these babies in the dishwasher! We are really happy with these tumblers. The design fits nicely in your hand and makes a great addition to our ever growing collection. Watch the Crew Review video below and then head over to our YouTube channel to see what else Gail has been playing around with!