If you are manually inserting coils, then these pliers are invaluable, as crimping the end of the coil ensures that the coil stays put.
Plastic Binding Covers
Renz Binding Wires A4 23 Loop 2:1
Presco Binding Wires A4 34 Loops 3:1
Leathergrain Embossed Card Binding Covers - Pack of 100
Presco Premium Binding Wires 2:1 Pitch A4 Wiro - 23 Loops