Well it's a fanny pack so...
Size guide
| S/M | M/L | |
| Fanny Pack circumference (inches) | 27 ⅝-37 ¾ | 35 ⅜-52 ⅜ |
| S/M | M/L | |
| Fanny Pack circumference (cm) | 70-96 | 90-133 |