材质 
M12
1.25|1.5|1.75
17
16.57
20.1
10
9.64
3.5
3.8
19
18.67
5.7
6
M14
1.5|2
19
18.48
24.49
11
10.57
3.5
3.8
22
21.67
6.64
7
M16
1.5|2
22
21.48
26.75
12
11.57
4.5
4.8
24
23.67
6.64
7