| Flexnumber | Piston | Piston Type | Top Plate Hole/Stud Qty. | Bottom Plate Hole/Stud Qty. | Top Plate Dia. | Bottom Plate Dia. | Collapsed Height | Type | Remarks |
| 21C | 3122 | 5 | 4 | 11.31 | 11.31 | 3.12 | Double Convolute |
| Flexnumber | Piston | Piston Type | Top Plate Hole/Stud Qty. | Bottom Plate Hole/Stud Qty. | Top Plate Dia. | Bottom Plate Dia. | Collapsed Height | Type | Remarks |
| 21C | 3122 | 5 | 4 | 11.31 | 11.31 | 3.12 | Double Convolute |