SDI-2000 - Portable Silt Density Index SDI Test Kit, directSDI SDI unit is completely assembled in a portable case, ready for manual, on-site testing. Includes ASTM instructions for measuring silt density index. Minimum of 30 PSI water pressure required. Optional Pump Assembly Kit available (model no. SDI-PU). Test Membrane Filters sold separately (model no. SDI-045). The perfect solution for portable silt density index (SDI) testing.