This is an antique C. S. Osborne Co., 6" compass/divider tool. Side is stamped C. S. Osborne Co. , Newark, N.J. The number is not stamped on compass but I believe this was a No. 28, 6" common compass in C.S. Osborne & Co. catalog. Toolmeasures 6 1/8" long. It is is very good used condition.All the parts are t and has really thick, good metal and still tight action. This compass is built like a tank. I'll let the photos tell the rest.