UN Photographics - made in Japan of excellent quality. These adapters are used to attach strobes and other accessories to arm systems using arm clamps.
... Well this was to be an exciting one Son Fletcher had recently attained his PADI Advanced Open Water and Enriched Air Specialty qualifications, so this was to be a deep(ish) dive on Nitrox. Conditions were surgy but not too unpleasant on the dive boat ...