Overview of Futurematic calibers:
497
497/1
827 - all above are hand-style powerreserve.
817
817/1
837 - all above are "port hole"
Somewhere on this forum are production figures posted...
From my memory the cal. 837 has a run of 500 pieces.
The references E 501 and E 502 are screw caseback and therefor "E"tanche.
Shown steel "port hole" watches are Clavi's (brown strap) the one with pink gold indexes is mine.
Cheers - Ilja