Serial no. 189522. Mfg. Beckman Instruments, Fullerton, CA.
pH meter, Model G
Serial no. 143220 (in lid; lid is detached). Manufacturer: Beckman Instuments, Inc., 1957. Similar to ST-BE-18. Original case is formica with lid (detached, no hinges or handle); lower door missing. With original instructions inside lid, dated January 1957.