To replace the rear emergency exit window on your Keystone Montana 3402RL, you'll need to confirm the window measurements and identify any manufacturer labels or part numbers on the window frame or remaining glass. Keystone Montana RVs often use specific window models depending on the year and layout, so having your RV’s year and any markings will help ensure an exact fit. We recommend inspecting your existing window frame for manufacturer information or sending us a photo for verification. Once you have these details, we can match you with the correct replacement emergency window that meets safety standards and fits your RV. Reach out to us with the specifics, and we’ll guide you through the ordering process.