The S4 Stair Mechanism V4 (2026) is the latest refinement of our original S4 design, first introduced in 2017. The S4 system supports 9 different module types, all designed to be fully interchangeable. Each module can be placed in any of the four positions, allowing countless configurations and motion variations using the same base machine. 🔹 Model: S4 Stair Mechanism 🔹 Version: V4 (2026) 🔹 Original release: 2017 🔹 Base layout: 4 module positions 🔹 Available modules: 9 types (fully intercha