A system and method for detecting casing is provided. The heater assembly includes a support member, a heater, and an actuator for extending and retracting the heater assembly. When threads are created for either operating system, the thread’s corresponding processor memory is mapped into an effective address space. In some embodiments, the second diameter is less than the first diameter, the second material is softer than the first material, and the second pitch is more open than the first pitch. The gas filter of the invention can be used over relatively long periods of time since it is regenerable.