The major obstacle to creating perfect ultrathin sections is compression, which can be as much as 20% at room temperature and significantly limits quality. DiATOMEs Ultra Sonic is a patented oscillating diamond knife that produces ultrathin sections almost free from compression for room temperature ultramicrotomy. A piezo actuator produces an oscillation of the knife at a desired frequency (20 to 45kHz) and amplitude, in parallel with the cutting edge. The 35° angle, 3.0mm knife produces section thicknesses ranging from 10 to 80nm.