Currently, there is no retractable shower door specifically designed for the 2018 Winnebago ERA 170X model. However, many customers successfully customize our retractable shower doors to fit their RVs. The canister that houses the door has approximate dimensions of 2.25 inches deep by 2.5 inches wide, making it compact enough for tight bathroom spaces. It is typically mounted on the inside of the door frame but can be offset slightly from the wall mounting rail to accommodate different installation needs. For your shower opening measuring 41.5 inches wide by 63 inches tall (or 42.5 inches wide if mounted outside the doglegged door mount), these dimensions help in exploring suitable custom options. We recommend consulting with a specialist to determine the best mounting door configuration to ensure proper fit and function in your Winnebago ERA 170X.