Most cups change your drink. Plastic leaches. Metal imparts a faint metallic taste. Both materials are doing something to what's inside, subtly, every time. 

Borosilicate glass is chemically inert to drinks. Whatever you put in tastes exactly as intended. Your drink touches nothing but glass. 

VITRI cups are double-wall insulated, so they keep drinks at temperature longer and the exterior stays comfortable and dry. No condensation ring on your desk. No heat on your hand from a hot drink. 

Two cups. Two glass straws. One gift-ready box.