This toy was made by a company called E. Joseph Cossman & Co., probably in the late 50s or early 60s.  I guess it was made under some kind of arrangement with U.S.Divers, since it looks so much like their equipment.  Basically, it is a fancy looking snorkel for kids to breath through on the surface and make believe they were scuba divers.  The air is drawn through the hole on the back of the "regulator".  Something is rattling around inside the "regulator".  It may be a valve to close the snorkel if the child went underwater.  The "tank boot" can be unscrewed and filled with sand to give the "tank" proper ballast but it is missing.  There is a nice Surf-Lung sticker on the "regulator" as well as one on the "tank". The hoses are broken and somebody tried to repair them with black electrical tape but that has started to come off.  This is a rare toy as most where played hard with and they rarely lasted to today. This item will not ship between Nov 2 through Nov 18.