You are buying one 20 Farad Capacitor with Digital Voltage Display
Why use a power capacitor? Power capacity is an energy storage device. It is designed to supplement you car's charging system, when your audio amplifier places a high current demand upon it. This occurs, for example, when the music you are playing contains a loud, transient, deep bass signal. The overall bass response of your system will be enhanced by using this device. Since automotive batteries are not designed to deliver the current required by modem car audio systems, a capacitor such as this one, which is capable of discharging extremely rapidly on demand, is a logical addition to your audio system. In addition, this capacitor can filter out the AC voltage induced in the amplifier’s power supply. Unchecked, this voltage can cause audible noise in the sound system. 
This capacitor is  good for amplifiers 
with 10000 watts in 4 ohm 
or with 5000 watts in 2 ohm 
or with 2500 watts in 1 ohm 
(You can never have too much capacitance for any audio system)

I personally checked this unit and it is in excellent working condition.
If user manual is available for this model I will send it for you otherwise if you need the user manual please send me an email and I will email the link for downloading.

The capacitor must be charged BEFORE connecting the POSITIVE wire to the capacitor. To charge capacitors, connect the capacitor negative screw to ground and then connect the positive screw of the capacitor to one leg of any automotive or landscape light bulb then connect the other leg of the bulb to positive wire from your car (+12 volt DC).
If the capacitor has remote power terminal (3rd smaller screw) connect it to the head unit remote wire (+12 volt DC) this connection is necessary in order for the digital display to work.


There are some youtube videos that you also can watch to help you installing your capacitor. Copy these 3 youtube links to your browser one at a time to watch.
http://www.youtube.com/watch?v=qxEp2OPMY6w
http://www.youtube.com/watch?v=QCPm8_QTVk8
http://www.youtube.com/watch?v=bY7LLX2goOQ

Picture is to show what the item looks like. Item you receive may vary slightly from this picture. This item may be a floor model or store return that has been refurbished. This item may have some signs of cosmetic wear, but is fully operational and functions as intended. 
 Features:

 

 

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I accept the following forms of payment:

·         PayPal: I prefer payment through PayPal and items will be shipped to Paypal address only. If you need to change shipping address, please change it in Paypal first before you buy, as I will only ship to your Paypal address.

·         If you prefer other method of payments, please let me know and I will change the payment method for you.

·         If you need additional time to pay for this item, you must notify me by email so I change the payment requirement.

Shipping

 I use paypal USPS shipping. I ship to paypal registered shipping address only please check your address before paying. Tracking number will be emailed to you from paypal once your item is shipped. If you don’t receive an email with tracking number from paypal please let me know and I will provide tracking number for you. I recommend you purchase additional warranty from Square Triad if available. All items are shipped from California, USA

·         Domestic:  Shipments to a USA address (50 states & Puerto Rico). Once shipped, the average Transit period is estimated 2-9 working days (It may take longer during holidays). US Postal Service is responsible for any shipping, which is out of my control.

·         I don't ship out of USA (50 states & Puerto Rico)

·         Handling Time: Once payment is verified, I ship within 3 working days (orders are typically shipped next working day) - weekends and holidays are not included. Please don’t hold me responsible for USPS slow shipping.

Exchange/Repair

I understand products sometimes fail and although I don’t manufacture the products myself, I will do my best to keep you a satisfied customer. Please understand I work at low margins so I can’t offer you reimbursement for return shipping or paying for overnight delivery, etc. but I will be HONEST AND FAIR. All I ask in return is that you work with me in creating win-win situation.

1.      To exchange or repair your defective unit please contact me by email to request for RA number within 30 days of receiving your item. Any returns without a RA number will not be accepted. Include a copy of ebay invoice and write the RA number on the invoice.

2.      Buyer is responsible to pay for return shipping and insurance.

3.      If the item found to be defective, it will be repaired or exchanged with a similar unit and returned to you at no cost. If the item is not repairable and/or exchange unit isn’t available; a refund will be issued.

4.      Original shipping cost is non-refundable.

5.      Return item must be in the original condition (not altered, or damaged) and should be returned with all original documents, parts/accessories and packaging. Any missing part will be deducted from the refund accordingly. Absolutely NO full refunds if I don't receive all the parts.

I take full responsibility for the items I sell. Please contact me FIRST to resolve any issues before leaving any Negative or Neutral feedback. (Negative or Neutral Feedback can't solve the problem). I will reply as soon as I see your email. I am offering absolute satisfaction.

Your purchase is subject to the policies listed above and reflects your agreement with these policies.

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If there is any kind of issue with your item that you are unhappy with please email me before leaving any kind of feedback. I will work with you to make sure that you are 100% satisfied. I will leave a feedback when I receive positive feedback from you.