Plastic binding now is considered to be the most popular binding methods;Widely applied to office equipment field;Competitive price and convenient operation.Shape: Round& OvalColor: Black, White, Red and BlueSize Available:Round:6mm,8mm,10mm,11mm,12mm,14mm,16mm,19mm,22mm,25mmOval:28mm,32mm,35mm,38mm,45mm,51mmRings Available:19 Rings& 21 Rings