Bassists like effects pedals as much as guitarists, they just never get to use them because so few pedals are geared toward bass. That problem ends here and now. Low End Friend puts back the low frequency content that guitar pedals remove. Place any effect in L.E.F.'s effects loop, engage both pedals, and then turn up the knob until your bottom end is as thunderous as it ever was. Low End Friend works by making a copy of the incoming signal, filtering off high frequencies, then adding it back to the pedal in the loop, resulting in a full frequency response. Unlike running a clean blend along side the effected signal, which can sound awkward and disjointed, L.E.F. just puts back what you lost. No blend controls, just turn the knob and your bass frequencies return. As much or as little as you need. Speaking of as much or little, some effects retain decent low end and don't need as much help. This is where the top switch comes into play. Up is a higher low pass frequency, resupplying you with bass and low mid frequencies, while down is a lower cutoff, focusing on only sub frequencies. Try both, see what feels right. Some pedals invert their polarity, making them hard to mix with other signals. Sounds that are out of phase will sound thin, hollow, and strange. Other products that came before Low End Friend suggested you kick rocks. You won't find that here. The polarity switch (bottom) ensures that your two signals are perfectly in phase. Not sure if they are in phase? Flip the switch. Better? Worse? Trust me, you'll know. Your days of making sacrifices based on the sounds you want are over. Low End Friend is here to help.