The D65 and D66 are 15 MHz and 25 MHz, respectively, all solid-state dual-trace oscilloscopes, in most respects their features are similar, where there are differences the text in ITALICS relates to the D65. An 8 x 10 cm CRT provides a bright and clear display. The dual-trace vertical system displays either channel separately, adds channels algebraically, alternates between channels or chops between channels at approximately 150 kHz rate. Channel 2 can also be switched to become the horizontal amplifier to provide equal X - Y displays. The solid state design, using FET input circuitry, provides minimum drift and fast stabilization time.