The BA and BB Series transient surge suppressors are heavy-duty industrial metal-oxide varistors (MOV) designed to provide surge protection for motor controls and power supplies used in oil-drilling, mining, transportation equipment and other heavy industrial AC line applications. These UL-recognized varistors have similar package construction but differ in size and ratings. The BA modelsa are rated from 130 to 880V M(AC) . Both the BA and BB Series feature improved creep and strike capability to minimize breakdown along the package surface. This package design provides both complete electrical isolation of the disk subassembly, and rigid terminals to insure secure wire contacts. Remove 'a package surface' second occurance. See BA/BB Series Device Ratings and Specifications table for part number and brand information.