GSI Outdoors Microlite 500

Insulation Don’t underestimate the thermal power of this sleek stainless-steel, vacuum bottle: “I burned my tongue pretty badly the first time I used it because my tea stayed so much hotter than with my old, bulkier double-wall mug,” reports one tester. The engineers at GSI are keeping mum about exactly how their “proprietary new forming process” packs such impressive vacuum insulation into a bottle no thicker than a standard Nalgene, but they will tell us it involves stretching the stainless-steel walls extra thin. After nine hours in a -5°F freezer, 500ml of boiling water was still 100°F.

Features A flow regulator in the top helps prevent big gulps.