4577 Mobile Step Masking Machine Astro Pneumatic The 4577 Mobile Step Masking Machine Astro Pneumatic 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 4577 Mobile Step Masking Machine Astro Pneumatic can also be used as a step stool.