Kemo VBF8 (8.03) dual variable filter system; 0.01 Hz - 100 kHz cutoff Used two channel filter system with variable gain (x1 / x10), low-pass / high-pass, AC/DC coupling, and a switchable response of either low-overshoot (Bessel, pulse response) or standard rolloff (48 dB/octave Butterworth). Cutoff frequency is adjustable in three digits and using one of five decades (0.01 Hertz - 99.9 kHz). The channels can be used fully independant, in series, parallel-add or parallel-subtract mode. This is a used system, and was recalibrated recently. Includes 3 months warranty.