A device is provided that may be adapted to control or monitor the pressure level of a fluid system. The device includes a member composed of a shape memory alloy in a superelastic state. The member is configured to undergo a phase change from a high modulus Austenitic phase to a low modulus Martensitic phase and stretch in response to an activation stress. In one embodiment, the member defines two ends such that one end of the member is operatively connected to a fixed point. Another end of the member is operatively connected to a movable element. As the member stretches in response to the activation stress, the movable element is translated relative to the fixed point. In another embodiment, the member includes two plates with respective holes that are selectively aligned when the first and second plates stretch or deform in response to the activation stress.