PQ-4 Parametric Equalizer THE PQ-4 has over time become quite rare. It was never a big seller and as Boss presently doesn't make any parametric equalizers, they are highly sought after. You can adjust Presence, Low Level boost or cut, Mid Frequency range between 100Hz and 1.6 KHZ , and a High Frequency range between 500HZ and 8KHZ. Each frequency range selector has it's own individual levels for boosting or cutting specific frequencies, plus it has a -18 to +18 over all level boost or cut. SpecificationsControls: Presence/Low, Middle, High, LevelConnectors: Input, Output, AC AdaptorCurrent Draw: 23mAWeight: 410gInput Impedance: 1 MohmOutput Impedance: 1 kohmResidual Noise Level: less than -98dBm (IHF-A)Recommended Load Impedance: More than 10kOhmRecommended AC Adaptor: PSA SeriesIn great shape for being 20 years old (it was made in Oct 1991)WORLDWIDE AND EXPRESS SHIPPING AVAILABLE!International Buyers: Standard shipping has NO TRACKING but a customs number. I recommend buying insurance $3. Express Shipping takes 5 days or so. It comes with a tracking number.Buyer is responsible for import taxes, customs fees, etc.