In the oil & gas industry, it is sometimes essential to be able to position two wells in relation to each other, for Steam-Assisted Gravity Drainage (SAGD) or for interception. This is where magnetic ranging can be very useful. Magnetic ranging uses a combination of magnetic sources and magnetic sensors to position boreholes accurately. Our high-temperature probes include the Mag610 and Mag611, which operate to 175^oC and 215^oC respectively. The Mag614, which operates to 175^oC, offers a compact design with a head measuring just 25x10x20mm. The noise performance of these sensors is unmatched in high-temperature probes, especially with the low noise version of Mag610. Low-noise measurement provides the highest precision measurement possible of the magnetic source, providing increased accuracy in determining the distance to the source. These probes are ideal for integration into compact downhole tools. We make available the electronics schematics, which means you can design your own high-temperature electronics for probe integration into a tool.