Selecting an Emergency Stop (E-Stop) button requires prioritizing safety integrity and environmental durability. You must ensure the device features a 'Positive Opening Operation' (IEC 60947-5-1), meaning the contacts are forced open by the mechanical action. Choose between Push-Pull, Twist-to-Release, or Key-Release mechanisms based on your specific safety protocol. For harsh environments, prioritize an IP67 or IP69K rating to ensure protection against high-pressure washdowns and dust. Additionally, verify that the button has a 'Trigger Action' design, which prevents the switch from changing state until the actuator is fully latched, eliminating accidental stops or restarts.