Mid-to high-priced amps may have other switches (which on some amps are switched on by pulling an existing rotary knob out) that boost or cut some part of the frequency range, such as "bright boost", "deep boost" or "mid scoop" switches. Amps with an onboard audio compressor or limiter, which is used to protect the speakers from sudden peaks in volume and from damage due to power amplifier clipping, may have only an on/off switch to turn on the effect (as with lower- to mid-priced amps), or they may have one or more knobs to control how much compression is applied to the bass tone (typically a ratio and threshold knob or just a single knob). Some 2000s-era amps may have an electronic tuner and a mute button, to mute the sound of tuning during a break between songs without having to change the volume settings. On some amps, vertical sliders may be provided to control a graphic equalizer, which gives the bassist control over a number of frequency bands.