Beal recommend the following number of turns around the rope when using a Beal Jammy*.
| Number of Turns | Prusik only | Prusik/French Prusik | Prusik/French Prusik |
| Rope Diameter (2 strands) | Jammy 35cm | Jammy 50cm | Jammy 60cm |
| 7.3mm - 8.1mm | 3 | 5 | X |
| 8.1mm - 8.6mm | 2 | X | 6 |
| 8.6mm - 10mm | 2 | X | 5 |
However, before use, the Prusik efficiency must be checked by the climber with their own rope as variations can be expected, for instance, new ropes can be very slippery so an extra turn may be needed.
* For ascending, we feel that it does not really matter that much if a loop is too long, so if buying a pair of prusik loops it makes sense to have two of different lengths to cover as great range of rope diameters as possible when using one loop as an autobloc.