Edelrid
Ohm $155
A great solution to the old problem of having one climber heavier than their partner. It adds friction so a lighter climber can control the catch of a heavier climber. The Ohm prevents the belayer from being pulled up, which can be dangerous to the belayer and climber. It dynamically adds friction, so the catch is soft. It adds no friction while feeding rope to a lead climber. Recommended weight difference between lead climber and belayer is 10 to 40 kg.