Sipster® cup uses the patented Playtex® SipEase® Valve: Eliminates messy spills; Easy to clean--all parts are top-rack dishwasher safe. Playtex® Cup Lid: Interchangeable with all Playtex® cups; With valve storage feature--no losing valve in the dishwasher! #1 Selling Spill-Proof Cup Brand 100% Spill-Proof, Leak-Proof, Break-Proof Guarantee BPA Free 12m+