Specifications include, but are not limited to: 1. The DLS instrument must perform measurements in situ in standard, commonly available and inexpensive 96-, 384-, and 1536-well plates. It must be capable of completing a measurement of all wells in a 384-well plate in less than 90 minutes with acceptable accuracy and precision. The DPRIII accomplishes this by design, is used commonly with all three plate types and at the stated throughput. 2. The measurements of multiple wells in the plate, and up to all the wells in a plate, must be performed in a fully automated manner after loading the plate into the instrument. 3. The measurements must take place directly in the well plate with no further l iquid handling besides loading the samples into the plate. In particular, the sample should not be extracted from the plate for measurement. 4. The instrument must provide dynamic light scattering (DLS) and static light scattering (SLS) measurements simultaneously. The DPRIII accomplishes this by design.