From Rockwell Automation (Milwaukee, WI) comes Allen-Bradley 855T Series B Stack Lights, suited for environments that are wet, dirty and corrosive.
Said to enhance productivity and safety while reducing maintenance and wiring requirements for harsh environments. Each module is a self-contained unit with all units in the stack powered from the base. No-tool installation. Can be wired using 12- or 24-vAC/DC 110-v AC or 240-vAC standard connectivity.