An always on Buffer and switchable 3 Band EQ. The buffer is helpful for long cable setups or when using an overabundance of pedals. The EQ is helpful in tailoring frequencies to specific parts, guitar switches or using it as an always on EQ. The Buffer is always on. The On/Off switch only activates/deactivates the 3 Band EQ. Controls : Low : Slide up to boost and down to cut a 100 Hz Shelf Mid : Slide up to boost and down to cut a 500 Hz Bell High : Slide up to boost and down to cut a 2 KHz Shelf Requires 9V 2.1mm negative center-pin power adapter (not included). mA Draw: 35