Yes, in most cases the bangles can be made smaller or larger. There are exceptions and these are noted in the product description. Bangles are enlarged by removing material from the interior of the piece. There must be sufficient wall thickness to allow this. Usually a combination of wall thickness and the desired size determine what can be done. Round bangles are made smaller by fitting a "sleeve" or liner into the piece and attaching it permanently. The liner is made of acrylic, not bakelite. We offer linings in black or white at no charge to the initial purchaser. Colored linings are available for an an additional charge. Please contact us for guidance in sizing.