The Slope effect pedal is a filter with 4 different modes, Lowpass, highpass, notch and bandpass.
highpass - Passes the signals high frequencies while attenuating (reducing the amplitude of) frequencies lower than the given cut-off frequency.
lowpass - Passes the signals low frequencies while attenuating frequencies higher than the given cutt-off frequency.
notch - Passes most frequencies unattenuated but attenuates frequencies in a specified range at low levels.
bandpass - Passes frequencies within a specified range and attenuates frequencies outside of that range.