Pre-formed plastic spirals are made from rigid PVC.
The thickness of the thread is from 1,91 mm up to 2,67 mm.

Price $ POA

Use this only as a guide. For accuracy measure thickness of actual book and use spiral diameter 2mm larger than book thickness for thickness 6 – 22mm and 3mm larger for thickness 25-30mm

RENZ PLASTIC SPIRAL
PVC Spirals 316mm   (A4)
Diameter   mm 6mm Pitch Digital Pitch 3:1 Pitch *For   approx. no of sheets 80GSM Quantity per Pack
6 X X 29 200
8 X X X 46 200
10 X X X 63 200
12 X X X 78 100
14 X X X 95 100
16 X X X 112 100
18 X X X 130 100
20 X X X 147 100
22 X 164 50
25 X X X 180 50
28 X 201 50
30 X X 220 50
32 X 260 50
35 X 300 50
38 X 330 50