We’ve taken our best-selling BOULDER bottle and added features that make it even better, setting it apart from the competition. Made from premium 18/8 stainless steel, it features our signature TriMax® triple insulation and keeps drinks cold up to 60 hours and hot up to 12 hours. he BOULDER stainless steel water bottle also includes a removable strainer for tea, fruit, and ice cubes. The fitted silicone bumper adds protection against everyday drops.