Produces the soundest castings. Actuated by an oversized steel spring, it utilizes a secondary arm pivoted to the main arm. Secondary arm carries the ring, keeping it in line with the casting force when the arm revolves. As a result, the cast metal travels in a straight line, directly into the mold, producing strong, dense castings. Comes complete with a CastRknob spin knob, which allows for easy and safe winding of the arm.3-1/2"D x 2-5/8"H