The test apparatus consists of a cylindrical metal container fit one end with water inlet and the other end with an outlet connection, of a standpipe tube with scale and a stand to support the pinhole apparatus. Certain fine-grained soils with high sodium content are highly erodible by the water flowing through them. During the test the flow of water under a high hydraulic gradient through a cavity in the soil is reproduced. 

Weight approx.: 3.5 kg