If there is a significant difference in weight between lead climber and belayer this frequently causes problems. This applies in particular to climbing couples, where the woman is often significantly lighter than her partner.

In the event of a fall, a lighter belayer can be suddenly pulled off the ground and hurled against the wall. In addition, when a belayer is pulled high off the ground, this significantly increases the distance that the climber falls. If the climber is still near the ground, belayer and climber might collide. In the worst-case scenario, the climber might hit the ground.

Using a weight bag to reduce the difference in weight is not possible all the time (nobody wants to carry a weight bag to the crag). In addition, weight bags restrict a belayer's freedom of movement. And even when using a weight bag, the belayer still has to supply the full braking force (with the associated risk of friction burns as the rope runs through belay device).

Due to its design, the OHM in no way restricts the handling of the rope for the lead climber. It does not increase the friction for the lead climber, nor does it negatively affect paying out the rope. The braking performance only comes into effect if a fall occurs. Due to the increased friction, lowering a heavier climber is also much easier to contol. Therefore accidents when lowering can be avoided.

In this way the OHM assists both the belayer and the lead climber.
The belayer will no longer be slammed against the wall. The lead climber can go right up to their climbing limit, with the reassuring knowledge that the belayer can secure them or that the landing will be soft.

The German Alpine Club (DAV) recommends that a lead climber should weigh a maximum of 10 kg more than the belayer (for example, belayer 60 kg/climber maximum weight 70 kg). If the lead climber is more than 10 kg heavier than the belayer, then weight or friction-enhancing measures are recommended.