The Seymour Duncan STC-3A is a three-band set of on board Tone Circuits that add tremendous tonal versatility to your electric bass guitar. This system is designed to work with active bass pickups. The STC Tone Circuit system enables the player to add to subtract EQ at center frequencies voiced specifically for electric bass. The STC Tone Circuits feature low noise, low distortion and high headroom, and are useful for all musical styles and genres. The STC-3A has three bands of active EQ, master volume and blend, plus the proprietary Slap Switch. The lows are deep, clear, and tight. The mids range from ultra-smooth to punchy and all points in between. The treble control can produce a very wide, very usable response that is brilliant, yet smooth without any brittleness. Pulling up on the volume knob engages the proprietary Slap Switch, a special EQ contour made just for slap-style playing. Includes all necessary mounting hardware: high-quality potentiometers on pre-wired harness; battery clip; stereo jack; and black anodized, knurled, dome-style knobs. For nearly all dual pickup basses. Can use 18 volts for increased headroom. Players include John Pena / Herbie Hancock, Bakithi Kumalo / Paul Simon, Doug Pinnick / King"s X, Chris Chaney / Jane"s Addiction, Tye Zamora / Alien Ant Farm, Sam Rivers / limp bizkit.