Ikelite Underwater Digital Camera Housing 6037.12 Hermes Typewriter I can't figure out what

I can't figure out what the purpose of the clamp is

Note the cursive tag which Bean ceased using in 1968

This Horseman 985 is a 6x9cm format rangefinder technical camera manufactured by Topcon in Japan

This biography of the famous astronomer reveals the man who offered observational evidence supporting the theory of the expanding universe and demonstrated the existence of other galaxies

Smith-Corona SCM Sterling

Ikelite Underwater Digital Camera Housing 6037.12 Hermes Typewriter I can't figure out whatIkelite Underwater Digital Camera Housing 6037. 12, originally for the Sony VX2000 VX1000 cameras, it looks like a clear gallon sized paint can with cast aluminum end caps and a removable heavy metal base and handle. The entire unit can operate below 120ft. and weighs 22lbs. on dry land.