RockShox Flight Attendant Upgrade Kit – ZEB 29 170 SuperDeluxe 230 x 62.5 Standard DubPedal Sensor A1 – TREK Slash 2021-2022. The only automatic suspension system that listens to the rider and responds in real-time. Flight Attendant uses a suite of sensors to read rider and terrain inputs to anticipate the perfect suspension positionenabling you to ride faster ride longer and spend less energy adjusting your suspension and more time focusing on what matters most: the unbridled joy of riding. Flight Attendant Upgrade Kits include everything you need to upgrade your rig to an automatic suspension system.