Circumference | Diameter | |
Approximate measurements in inches | ||
4 | = | 1 |
7 | = | 2 |
10 | = | 3 |
13 | = | 4 |
16 | = | 5 |
19 | = | 6 |
22 | = | 7 |
25 | = | 8 |
28 | = | 9 |
32 | = | 10 |
47 | = | 15 |
63 | = | 20 |
GPG | PPM | |
---|---|---|
Slightly Hard | 1.0-3.5 | 17.1-60 |
Moderately Hard | 3.5-7.0 | 60-120 |
Hard | 7.0-10.5 | 120-180 |
Very Hard | >10.5 | >180 |