These are Afghani Bangles. Kuchi & Boho people wear it in routine. These bracelets has lock system which is easily opened & closed. These bangles are having special design with Feroza stones fixed inside them.
Such type of jewellery is traditionally used in routine but can be used in special events like wedding or Nikkah ceremonies. Most of the belly art dance performers also like and recommend these bangles for best bellydance performance at stage.