Smaller-size nuts have hex flats, while larger nuts have spanner slots.
| Material | Heat Treat | Finish | DFARS | RoHS |
| Steel | - | - | Yes | Yes |

| Fits Standard-type Swing Clamps | Fits Robust-type Swing Clamps | D Diameter | E Diameter (Inch) | F (Inch) | G | T (Inch) |
| 2 & 3 Series | Robust 4 Series | 20mm | 0.925 " | 1.18 " | M18x1.5 | 0.354 " |