Sea to Summit Frontier Ultralight Collapsible Cup

The Frontier Ultralight Collapsible Cup is a 400 ml silicone drinking cup reinforced with a glass-reinforced nylon frame that keeps its shape when full and insulates fingers from a hot drink. At 53 g and 101 mm across by 88 mm tall when open, it collapses down to just 1.6 cm, small enough to disappear into a pack side pocket or slot into the wider Frontier nesting system alongside the pot, bowl, and spork. It is built for drinking rather than direct heat exposure — suitable for both hot and cold beverages, but not intended for cooking or use directly over a flame the way the hard-anodized Frontier pot is. There is no lid, keeping the design as simple as possible for its size and weight class. This cup fits ultralight backpackers who already carry Sea to Summit's Frontier cookware and want a dedicated drinking vessel that adds almost no weight or bulk rather than drinking straight from the cook pot.