With Wave-and-Read technology, the DL-500 digital levels series provide an additional survey style option that allows a rod person to wave the staff back and forth instead of keeping it plumb. When standing vertically, the reading becomes the minimum; as the staff is waved, the least value is read, reducing errors and operator eyestrain. The DL-500 also features Random-Bidirectional (RAB) code for optimum digital processing algorithm for staff reading. Invar-, fiberglass-, and aluminum-RAB-code staffs are available. Topcon Positioning Systems Inc. 800-443-4567. www.topconpositioning.com