[3 Set 3 Ring Binder Mechanisms]: Package includes 3 set ring binder replacement kit binder mechanism: 4.35cm(1.71in) wide 27.8cm(10.94in) long 4.35cm(1.71in) thick hole: 5x4mm(0.2x0.16in) inner diameter: 38.5mm(1.52in); screw: 9.5x8mm(0.37x0.31in) pin: 3mm; nuts: 8x3.5mm(0.31x0.14in) hole: 3mm. [Easy to Use]: The ring binder replacement kit can be divided into two halves. Place paper with holes into the ring and then close the circular ring. The book binder is securely locked to prevent the paper from falling off or loosening. [Iron Material]: The binder rings mechanisms are made of iron which is not easily broken or faded. It is sturdy and durable and the circular ring allows you to quickly scroll through the pages. [DIY for Fun]: The 3 ring metal binder mechanism is very suitable for DIY. You can put different colors and shapes of paper into the circular ring customize a notebook for yourself and enjoy the fun of DIY. [Wide Applications]: You can not only make new notebooks books etc. with binder rings mechanisms but also use them to replace old binder mechanism.