XS series
The Dwarf Boxocket series
This series started in 1929 under the Blue Point name. The series changed a little over time with smaller and larger sizes being added and the name switched to Snap on in the 1950s (pre 1953) . Basically, there are a lot of these out there. They range in dates from 1926 through the 1970s. They came in basic sets, so the wrenches in these basic sets are much more common than the wrenches at the extremes that were not sold in sets. There are also a lot of variations. The stock or model numbers help date them in the variations.
The wrenches I know exist from the catalogs are