The Sirius Star CT-503 has two rolls, much like the wringer of an old-fashioned washing machine. Both rolls have a small diamond pattern ("knurling") machined directly into the metal to grip the canvas. The bottom roll is turned by the handle, but cannot move vertically. As it turns, it drives the top roll through a train of gears. The upper roll both turns and can be adjusted up and down. The two rolls turning together pull slabs through easily, and the vertical adjustment of the top roll gives an easy-to-set and infinitely adjustable thickness from paper-thin to over 2 inches. A reference scale allows setting and repeating openings to within 1/100 of an inch.
The CT-503 rolls slabs up to 28" wide and comes with a crank handle and two sheets of 36" long canvas.