From the Classic Collection, this Semi-precious Onyx Pendant has the Signature Bulova Tuning Fork Charm, set in Stainless Steel. One size fits all. Round Box Link Chain that is adjustable from 26" inches to 28" inches. Signature Lobster Claw closure. Pendant dimensions: 36mm x 12mm x 4.2mm. Black onyx is believed to aid the development of physical strength and stamina and is a powerful protection stone.