Rear seat backrest lock - BA91.12-P-1000-01B

WARNING: This page does not describe the selected car, but rather 203 other vehicles, including the 2020 Mercedes-Benz SLC300, 2020 Mercedes-Benz SL550, 2020 Mercedes-Benz SL450, 2020 Mercedes-Benz S65 AMG, and 2020 Mercedes-Benz GLA250. However, it is still accessible from the selected car via links, so may be relevant.