This handmade gauge is also on loan to www.TheSCUBAmuseum.com from the ATRA collection in Germany. It is believed to have been handmade in about 1960 by the late Jan "The Sharkman". Jan was born June 21 1954 and died May 19 2006. Jan was a Polish Navy diver, great friend to Arkadius Oszczygiel, and teacher to many he will be missed greatly. Any other information about this gauge or Jan is welcomed.