A sizing screen similar to the shaking screen, but the reciprocating movement imparted to it is of greater frequency and much smaller amplitude--1,000 rpm and 1/4 in (6.4 mm) being typical. High-frequency vibration is more effective than the slow movement of the shaker in preventing blinding of holes, and the screening is more effective. It may contain one, two, or three screen decks with water sprays for washing products when screening. Five products ranging from plus 3/4 in (19.1 mm) to minus 1/8 in (3.2 mm) are possible from a double-deck screen. In general, the screen is inclined at from 12 degrees to 14 degrees for the coarser sizes and 17 degrees to 21 degrees for the finer sizes with counterflow operation.