Boss LMB-3 Bass Limiter/Enhancer Pedal (Used) Fretless Bass Guitar As you raise the control

As you raise the control the Depth and Rate LED will start to glow giving you a visual indication as to the amount of modulation you are applying to the repeats

There’s also an internal trimpot which provides adjustment to fine tune the self-oscillation

also contributes to the single coil bounciness and snappy low end

Here is the write up from the Gibson catalog at the time

Boss LMB-3 Bass Limiter/Enhancer Pedal (Used) Fretless Bass Guitar As you raise the controlThis pedal is in very good condition with minor cosmetic wear. It has been fully tested and is working with no issues. The original box is not included. From Boss LMB 3: Bass Limiter Enhancer The LMB 3 affords complete control over a bass guitar's dynamic range using a limiter effect and an enhancer circuit designed specifically for electric bass. Full control of bass guitar's dynamic range via threshold level and ratio knobs Enhancer provides