Improved Thermal Stability
Air currents can have a significant impact on thermal stability, particularly with large cold plates like the 264. For applications that need a very stable reponse, the 260-C is a custom designed cover that fits snugly on top of the fixture, and can be bolted down to prevent removal.

Nitrogen Purge Fitting
The 260-C also includes a 1/8" barbed nitrogen purge nipple to purge the cavity to prevent condensation when operating below the dew point.