911Met
I have used the rp4 (did not go by that name either) a few years back but it did not work well due to the way it was installed. They have to be
leveled, and anchored securely. The one I have used was not anchored well so the concentration levels were
not as good as could be. As of this writing there are two different shaker table sizes; one is 43 x 17 and the other is
smaller but both are the same price, and the metal base is extra cost.