David,Hurricane manufactured a second snorkel valve called the Hurricane Automatic Valve.
Hurricane Automatic Valve
View attachment 494300
Caption in English: "Hurricane AUTOMATIC valve. Fits any CURVED breathing tube. The patented valve shuts off at the slightest contact with water. This valve closes when submerged and seals the air intake in all positions.
This device puzzles me because I can't tell whether it is intended for a J-shaped or S-shaped snorkel. Perhaps, dear reader, you may be able to offer suggestions.
Otherwise, that's enough for today. Next time I will review Hurricane brand combined snorkel masks. Stay tuned.
This attachment had to be or either a "C" or "S" shaped snorkel. It could not have been used for a "J" snorkel, as there is only one opening. If used on a "J" snorkel, the opening would be blocked by the ping pong ball (or whatever float was used) falling down by gravity.
SeaRat