Amazon.com : Akiles ADM-C51 Model DuoMac-C51 2-in-1 Combo Binding Machine, 5:1 Pitch Coil with Built-in Comb Opener (1/4" to 2"), 20 Sheets Single Punching Capacity (20 lbs Paper), All Metal Construction :
Akiles DuoMac C41ECI+ Plastic Comb and 4:1 Coil Binding Machine – Printer's Parts & Equipment -USA
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Akiles DuoMac C41 Plastic Comb and 4:1 Coil Binding Equipment – Paper Machines