The Strata II valve and Strata NSC valve is considered Magnetic Resonance Conditional in accordance with ASTM F2503. MRI systems of up to 3.0 Tesla may be used any time after implantation and will not damage the Strata II valve or Strata NSC valve mechanism, but can change the performance level setting. The performance level setting should always be checked before and after MRI exposure. The results of the tests performed to assess magnetic field interactions, artifacts, and heating, indicated the presence of the valves evaluated should present no substantial risk to a patient undergoing an MRI procedure using the following conditions: