The inner ring reduces pop-off incidents, providing a more secure lid fit and reducing dribble at the rim and cup seam. Use with: IC8-J8000, IC8-J7534, 378RC-J8484, 378PLA-J7234, 378SH-0041, 378SI-0041, 378HJZ-00055, 378JZ-00055, 378HS-0029, 378MS-0029, 378HSM-J800, 378SM-J8000, 378HW-2050, 378W-2050.