Diameter（mm）

spring tube

6

7

8

10

12.5

Correspondence diameter of hole

3

3.6

4

6

6

The diameter of spring tube core

2 or 2.5

2.5

2.5

4 or 4.5

5

      Diameter（mm）

Straight wire tube

7

9

10.5

11

12.5

15

Correspondence diameter of hole

3.2

3.7

4.5

5

5.5

7

The diameter of spring wire tube core

1.9

2.3

3.3 or 3.5

4.1

4.5

6