This is a pair of Japanese, folding, pocket-size binoculars in a snap-shut, clam-shell case. They were marketed as opera glasses or field glasses for outdoor events.
The hard metal case has a crisp, sprung, shutting mechanism which protects them and makes them easy to handle.
Magnification is x 2.5, which is not good enough for Coastguard use but still useful, considering their compact size. We use these ourselves for garden bird spotting and they take up no more room in a glovebox or bag than a phone or pair of sunglasses. They also look great.
They're Japanese, sold under the name King and were probably made during the 1960s. They're marked:
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