M27C256B-12F6 by STMicroelectronics

This 256-kilobit ultraviolet-erasable programmable read-only memory (EPROM) from STMicroelectronics delivers reliable parallel data access with 120-nanosecond access time. The device features a 28-pin ceramic dual in-line package with frit seal and quartz window, enabling field reprogramming through UV exposure. Ideal for embedded systems, firmware storage, and legacy equipment requiring non-volatile memory with proven performance characteristics.