The Krohn-Hite 3500R Band-pass Filter has both high and low cutoff frequencies independently adjustable over the range from 20Hz to 200kHz. The response characteristic approximates a fourth-order Butterworth with maximal flatness for optimum filtering in the frequency domain. For pulse signal filtering, a switch is provided to change the response characteristic to damped Low Q response for transient free filtering of pulse type signals. The calibration accuracy is ±10%, insertion loss is 0 dB, maximum attenuation is 60 dB, and features floating (ungrounded) operation. Rack mounting version.