Zasady doboru grzbietu plastikowego
| średnica grzbietu | max oprawia kartek |
| 4,5 mm | 10 |
| 6 mm | 25 |
| 8 mm | 45 |
| 10 mm | 65 |
| 12 mm | 105 |
| 14 mm | 125 |
| 16 mm | 145 |
| 18 mm | 165 |
| 20 mm | 180 |
| 22 mm | 210 |
| 25 mm | 240 |
| 28 mm | 270 |
| 32 mm | 300 |
| 38 mm | 350 |
| 45 mm | 440 |
| 51 mm | 510 |
| średnica grzbietu | oprawia kartek |
| 4,8 mm | 2-15 |
| 6,4 mm | 16-40 |
| 8 mm | 41-55 |
| 9,5 mm | 56-65 |
| 11,1 mm | 66-80 |
| 12,7 mm | 81-100 |
| 14,3 mm | 101-120 |
| średnica grzbietu | max oprawia kartek |
| 6 mm | 30 |
| 8 mm | 50 |
| 10 mm | 70 |
| 12 mm | 90 |
| 14 mm | 110 |
| 16 mm | 120 |
| 18 mm | 160 |
| średnica grzbietu | max oprawia kartek |
| 5 mm | 25 |
| 10 mm | 50 |
| 15 mm | 75 |
