Occasionally we get back alternators from customers on stock adjustments or warranty repairs, where the customer chooses to upgrade to a higher amperage unit. These alternators are used, but are refurbished to like new condition and performance. They appear brand new, and have new rectifiers, regulators, bearings, and and rotors. Refurbished units come with a 90 day warranty, and can still be repaired inexpensively if the customer has a problem outside of the warranty period. This unit features a large case hairpin construction with huge press fit diodes, a heavy duty 2 pin standard GM voltage regulator, and a billet pulley. These units make a minimum of 200 amps at idle with 320+ amps at cruising speed. (most typically make closer to 350 amps peak) These units are a great way to get big power on a budget. NOTE - Like most high output alternators these units come with a smaller pulley, and will require a slightly shorter than stock length belt, which can easily be purchased from your local autoparts store. ALSO: THIS ALTERNATOR WILL NOT BOLT ON TO YOUR PUEGOT, VW, HONDA, LAWN MOWER, OR NISSAN PATHFINDER. IF YOU DO NOT HAVE A 2005-2013 GM FULLSIZE GAS ENGINE TRUCK, PLEASE DON'T ASK! LOL. ALSO: PLEASE FOLLOW THE SUPPLIED INSTRUCTIONS- 2005-2019 GM trucks cannot do the standard "big 3" upgrade like everyone describes on the internet. There is an inductive load sensor that goes around the OEM negative battery cable, and the positive and ground cables to the alternator need to be run in a very simple way- If you want your alternator to function properly with your truck's RVC system, please disregard the genius's on the internet, and read the detailed colored two page instruction sheet that we supply with this unit. It is very easy to install if you just follow the directions.