The Rotap Shaker is durably constructed and is run by a 1/4 H.P. electric motor. Running parts operated under oil. Machine is easily installed. No foundations are required. It reproduces circular and tapping motion with a uniform mechanical action. It ensures accurate and comparable results with uniformity not obtainable in sand testing. It can accommodate 6/7 full height with one set of lid and pan 20 cm dia sieves