The Uppababy Mesa isofix base is compatible with the Mesa car seat (sold separate). This provides a smart, secure system with an electronic indicator panel that gives visual and audio confirmation. It guarantees the Mesa i-size car seat is installed correctly the first time and every time. The system includes a unique tension indicator, ensuring the base is properly positioned to the vehicle seat, significantly reducing misuse. The single action ISOfix release system allows caregivers to easily and properly install the base, removing the guesswork.