350ml volume, leakproof. Temperature variation from 
The white PP ring has to be removed and fit on when openning and folding. Before folding the cup, please keep the drinking hole openning.Just place your hand at the top and bottom flat and press together. It folds down easily and opens just as easily as collapses it can.
Non toxic and no after taste or odor. It is made of 100% food grade Silicone & PP. BPA Free, FDA approved.
HEAT PROTECTION: The white PP ring makes the coffee mug easier to hold, drink from and heat protection.
It helps stabilize the cup and keep it in shape. Please make sure to fit this PP sleeve before you fill with hot liquid to avoid scald.