This is a Wonderful Vintage Pearlized Lucite Plastic Bangle. It looks like the Lucite they would use in a Purse or Accordian.
It measures 2 1/2" across the inside and it varies in width from just about 1 1/2" down to just over 1". It is in Very Good Condition.
Pearlized Lucite Asymmetrical Bangle Bracelet