I have hunted with a kellar and loved the simplicity of it,it was very accurate out to 35 yards.It was nice in the heat of the moment to just concentrate on the shot and not worry about the yardage.I shoot a single fixed pin today because of the speed of modern equipment.My single pin will shoot flat out to 30 yards.A pendulum was a good tool,when the bow speeds were slower,but with modern equipment,I don't think they are needed.