Signed OC and the British Hallmarks, one is a lion for sterling, then a lions head for London and then what looks like an X, although I cannot find X in the letter dating, might be another makers mark? The Hallmarks are very tiny and the heart pad lock is engraved MAY 1967 (which can be buffed out). Very nice quality and solid curb chain bracelet with a heart pad lock closure. The heart has a safety chain and is secured by pushing in on the top to pop the arm into the top of the heart. Very nice piece of British sterling jewelry.
The bracelet is 7 1/2" around by 0.4" thick, the heart is 0.8" tall, including the arm by 0.6" wide, weighs 20 grams.
Signed British Sterling Pad Lock Curb Chain Bracelet circa 1960