Metal Bangle/Bracelet with three balls inside hollow rim

I came across this seen better days bangle in a charity shop but was puzzled by what was inside the rim of it, so please can anyone help to enlighten me.
Inside the hollow of the bangle inside are three tiny balls? And a white rectangular shaped piece all glued in. Further along there are some other markings, dont know if at one time the whole rim was filled with balls and if so whats the white piece?
Ive put tube, tubular, slave bangles in and cant find anything. Just curious to know or if its just the jewellery makers signature.
Please help!