Screw binder mechanisms - ideal for storage bigger quantity heavy documents (lower risk of undesired opening what could happened with ordinary mechanisms)

From specification:

Nickel plated,

Ring distance 80 mm

Ground plate: 92 x 53 x 0,8 mm 

Thickness of the ground plate about 1.0 mm 

Rivet hole diameter: 4.5 mm

Price for one pc - bigger quantity available

Combined shipping possible