The S series box lock O/U shotguns were available from 1956 to 1971 with 12 or 20 gauge chambers and single selective triggers. The S55 features a satin chrome finished action fitted with blued ventilated rib barrels, manual extractors and no side ribs.
The S56 E features a satin chrome finished engraved action fitted with blued ventilated rib barrels, side ribs and automatic ejectors. In addition the stock was of a select grade walnut.
The S57 E had the same features of the S56 E but was finished with a higher level of hand engraving, walnut stock and was fitted with corrosion resistant polished blued barrels. A later version was offered with side plates and more elaborate engraving, this was known as the S57 EL