| Flexnumber | Piston | Piston Type | Top Plate Hole/Stud Qty. | Bottom Plate Hole/Stud Qty. | Top Plate Dia. | Bottom Plate Dia. | Collapsed Height | Type | Remarks |
| 321C | 4311 | 25.13 | 25.13 | 4.3 | Triple 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 |
| 321C | 4311 | 25.13 | 25.13 | 4.3 | Triple Convolute |