As space projects have matured, higher voltages have become a requirement leading to the 270 Series. It is not always feasible or desirable to split a circuit or add a relay or keep the current under 1 ampere by whatever means.
Many of the same practices and processes apply to both the 270 and 700 Series; for example cleaning to no particles greater than .001" 100% verified by micro-particle analysis. Some less so, for example "dry circuit" testing at endurance for the 700 Series versus 10 amperes at 28Vdc for the 270 Series.
The 270 Series evolved from a device designed and built for demanding industrial applications. This configuration is qualified to NASA Goddard S-311-641 and S-311-641/04. The design is continuously qualified (every sealing lot) and improving.
De-rating is encouraged.
Thermal switches exported from the United States must be done in accordance with the export administration regulations (EAR) and/or the international traffic in arms regulations (ITAR) as applicable.