Not many surviving examples of this particular rule which seems to be outshone by the wider No. 13 1/2 variant which can be found quite readily. Circa 1923 ~ 1932 based on the "STANLEY SW" logo. This caliper rule was later discontinued in 1933. Single alignment pin is sound. Fine overall condition noting a marginal sliver off the boxwood on the back by the "2". Uncleaned as found, but clean and sound!