Designed for the ThermoFlask® Travel Mug. One O-Ring and one Sip Plug are included in the pack. The O-Ring fits on the bottom of the lid while the Sip Plug fits inside the fliplock lid. Both items are BPA free.  Fits the ThermoFlask Travel Mug Top rack dishwasher safe  BPA Free  Note: This item ships via USPS First Class Mail.