eBoot 30 Ounces Tumbler Lid Spill Proof Lid for Yeti Rambler and RTIC Tumblers Mugs, 2 Pack (Light Blue);

Features:
Suction mouth can be opened and closed with the vane up or down. 
The black silicone o-ring around the base helps the lip cover the cup tight. 
The small air hole on top of slider based on airflow ergonomics helps reducing splashing. 

Specifications:
Color: light blue
Material: AS plastic 
Product diameter: 3.94 inches 
Product weight: 4.02 ounces 

Package contents:
2 * Spill and splash resistant tumbler lids

Tips:
It is easy to be cleaned with the detergent, so you'd better not wash it in a dishwasher.
The small air hole is designed to keep a same air pressure inside and outside of the tumbler. Do not block it with anything.
This lid will help with accidental tips and spills but not guarantee no leaks if inverted for a long time. 
When it is filled with hot drink, you'd better open the straw hole in case of the lip pop up for high pressure.