PI (Physik Instrumente) LP has released its S-303 series high-speed phase shifters for interferometry, optical path tuning, spectroscopy, beam stabilization, laser physics and cavity tuning applications. The compact systems, based on a tripod piezo drive that provides a resonant frequency of 25 kHz, offer angstrom-level (<0.1 nm) resolution with piston movement up to 2 µm, with submillisecond response and settling dynamics. They are designed for mirrors and optics of up to 1 in. in diameter and can be mounted in any orientation. Open- and closed-loop versions are available, as are low-noise analog and 20-bit digital controllers to drive the shifters.