Abstract: A gauge carrier having a sensor, a ball carrying the sensor, and shell surrounding the ball are disclosed. The sensor can detect at least one of pressure and temperature. The ball exposes a sensor surface to allow fluid to reach the sensor surface to take measurements. The shell, ball, and sensor combined can be configured to float or sink in water. The shell can be made of a dissolvable material that, after dissolving, allows the ball and sensor to float to the surface. The gauge carrier can withstand hydrostatic pressures exceeding 10,000 psi.

Abstract: A corrosion sensor and ball are disclosed. The ball is sufficiently strong to withstand at least 10,000 psi of well pressure, yet is light enough to float in a well. The ball also includes a dissolvable weight heavy enough to cause the ball and corrosion sensor to sink in the well. Once the dissolvable weight dissolves, the ball and corrosion sensor float to the surface for easy retrieval and analysis. The rate of dissolution of the weight can be tailored to adjust the time it will take for the ball to return to the surface.