Obviously we here at level Zero fill ours with GCS16 but you can put whatever you want in it. I guess.
.: Durable premium stainless steel material
.: One size: 30oz (0.88l)
.: Easy sipping, clear push-on plastic lid
.: Narrow mouth opening
.: Stipple print texture
.: NB! Full bleed designs suggested only on the silver color to avoid any unprinted gaps from the print and the silver ring
.: NB! Hand wash only