903379 Bumper aero 966-977 plus inserts L+R 903618 Aero bumper inserts L+R 977 For the Serpent 966 ( all versions) and Viper 977 ( all versions) Serpent introduce this new version of the front bumper, which features click type inserts on the left and right. Serpent teamdriver Merlin Depta came up with this idea, so you can change fast between racing with or w/h inserts. It s a few second job to insert or remove. Once inserted they click really firmly in place. Running without inserts normally gives more steering, especially in high speed corners. Yet its al about set-ups and testing, and for sure its very easy to change it fast now. The Aero bumper sells as set with inserts, and the inserts separate.