The Gemini family of Dry Blocks have high capacity, allowing a large number of probes to be calibrated together. This dry block calibrator is also suitable for large-diameter probes with the block volume of a nominal 65 x 160mm.

While the large block takes longer to heat and cool than the Jupiter 650 and Fast-Cal models, it can calibrate thermocouples, resistance thermometers, thermostats, and sensors that are too large for the smaller blocks.

This digital temperature calibrator is available with a fixed-block with four 8mm and four 19.5mm pockets, or the LRI version, which has a removable block. With the LRI model, blocks can be drilled to custom configurations.

The Gemini is available in two temperature ranges, with each available as a BASIC (B) or SITE(S) variant. The B model includes a sophisticated temperature controller with a dual display for Set Temperature and Dry Block Temperature.

The S model also includes a built-in digital indicator to which an external standard thermometer can be connected, giving greater accuracy, eliminating temperature gradient and loading errors. For lab accuracy, the Gemini ^PLUS can be used with a high-end temperature indicator, such as one of the Isotech True Temperature Indicators (TTI).