Astro Pneumatic Mobile Step Masking Machine 4577 The Astro Pneumatic Mobile Step Masking Machine 4577 is lightweight, easy to use and portable, and can dispense rolls up to 18” wide. A sharp, anodized blade allows for smooth cutting. With a load capacity of 220lbs, the Astro Pneumatic Mobile Step Masking Machine 4577 can also be used as a step stool.