The Model S471, released by UDT Instruments, is a next-generation handheld optometer suitable for use in both laboratory and field environments. Its high sensitivity enables measurements in the 10-pA range, with less than 1% uncertainty. It offers computerized high-speed update rates of twice per second, or up to 53 times per second when computer-controlled with the display disabled. Data is presented via direct display measurement with analog bar, RS-232 interface or programmable analog voltage output. The device can be configured as a radiometer, photometer or fiber optic tester. It stores nine continuous calibrations or 50 single-point ones, and all are NIST-traceable. Features include a large monochrome backlit LCD for easy readout, long battery life, direct external power, a touch keypad and an optional USB-to-serial bridge converter.