[Vintagehamiltons]

Hamilton Sea-lectric II
catalogued 1961-1964
stainless steel weatherproof case
two dial options: white (most common) or gray (very scarce)
electric 500 movement and later, the improved 505 model
35mm wide case
42mm over the lugs
18mm strap width

 

[two21b]

My first thought was this reminds me of the Thor with the bottom cut off.