The beam is a beam with 3 levels of raengkratham is spinning with a strong point of resistance during the middle of lifting beam exert to overcome strong resistance where the beams will not help lessen.
3 bar level as a lever to force the pivot point resistance. You will have to physically lift the middle of the bar to overcome resistance. The beams of this type will not labor.
The beam level 3 beams with force between the pivot point and friction. By will need to exert lift in the middle of the beams to overcome friction. The beam of this type will not help your strokes.