Other aspects to consider in choosing a snap switch are listed here. Contact form includes Single Pole Single Throw (SPST) and Single Pole Double Throw (SPDT) while the contact ratings of the switch contacts are typically anywhere from 0.1A for low level switching, such as for logic levels, to 25A for high power switching. The electrical life of the switch correlates to switch reliability and the number of switching operations while the mechanical characteristics influence physical size, mounting and termination style, and actuator operating points. Finally, ingress protection refers to unsealed, for indoor applications, or sealed (or IP rated) for outdoor applications along with UL and CSA approvals for safety requirements.