The Humangear cupCUP is the civilized， 2-mode nesting cup system. This insulated mug converts into two separate cups. Go from a double-wall insulated mug with sipping lid to 2 single-wall cups when needed! The press-fit sipping lid with silicone gasket prevents leaks. The cupCUP fits seamlessly into the Humangear GoKit (sold separately) for easy， compact storage. Features: Converts from a double-wall insulated mug with sipping lid to 2 single-wall cups. Press-fit sipping lid with a silicone gasket to prevent leaks. Fits seamlessly into the Humangear GoKit (sold separately) for compact storage. BPA-free， PC-free， and Phthalate-free. Durable and reusable for a more sustainable lifestyle.