A nice quality luthiers' or violin makers' edge crack clamp.

From a retired luthier's workshop.

Believed to be nickel plated brass.

Cork and leather lined jaws.

Spring assisted adjustment.

All parts move freely and tighten securely.

Approximately 2⁵/₈ by 2¹/₁₆ inches (65 x 52mm) overall including the main screw.

Please see images.