C-Size VXI Mainframe, 6 Slots The Agilent (now Keysight) E1421B is a C-size, 6-slot VXI mainframe and a compact, cost-effective ,solution for configurations requiring fewer slots than the 13-slot E1401B or E84XX series C-size mainframe. The smaller size and weight of the E1421B make it an excellent choice for either portable or rack-mount applications. The E1421B complies with the VXIbus Specification by providing injector surface rails used by the QUIC easy module insertion and extraction system. 6-Slot, C-size Compact size Portable or rack-mount Ultra-reliable power supply Power supply serviceable through the rear panel Pressurized air channel cooling