Constructed specifically for use in taking rolled fingerprints, the frame is heavy-duty steel. The 4" roller is of medium-soft composition, ensuring an even distribution of ink. Using the ink roller, push and roll the ink over the slab until a smooth, thin layer of ink is formed. Then, begin rolling the fingers in the ink. Repeated cleaning with solvents will not damage this roller. Replacement rollers, including new end caps, are available.