This is for a lightly used Carnetix 2140 power regulator. I bought this to go with my laptop carpc that I had before changing to a MOCOSO computer to replace it. I never got this working quite right and therefore it hasnt been used very much. $80

Here is the description:
http://www.carnetix.com/P2140/CNXP2140.htm
Features
Dual Output Regulator for automotive, RV, truck, taxi, and marine applications
Total output power up to 250 Watts (24Vin/20Vout) or 185 Watts (12Vin/20Vout)
Compatible with 12V OR 24V systems (auto ranging, no jumper changing)!
Jumper selectable main output of +12V/+18.5V/+20V
Primary output capable of up to 11 amps at +12V (130 watts) or 7.5 amps @ 20V (150 watts)
Jumper selectable secondary output of +12V/+13.5V or +5V at up to 3 amps (36 or 15 watts)
Optional 3rd output using CNX-P5V/15 watt regulator
Includes sturdy aluminum chassis and variable speed fan.
Survives Engine Cranking under full load over entire temperature range
Includes sophisticated Startup/Shutdown Controller (SSC) with USB interface to your CarComputer
INCLUDES PSUmoni(tm) POWER SUPPLY MONITOR APPLICATION PROGRAM!
Firmware upgrdable using USB port. No PIC programmer required!
Low battery monitor (user settable threshold) prevents drained battery, even during Standy/Sleep
"Anti Thump" delayed remote control (DLYON) for audio amplifiers (user settable delay time)
"Deadman Timer" to cut power if your system remains in sleep/standby for too long (user settable time)
Remote "Pulse Start" from wireless device or car alarm/remote start system
Over current protection on both outputs with graceful forced shutdown of main output
Powers both your computer (PC or Mac) AND your screen or USB devices
Compatible with Mac mini including startup/sleep mode
Compatible with Aopen Pandora Mini PC
Compatible with +12V or +19V Pentium-based systems such as Travla, Sumicom, Xenarc SC3 & SC8, Commell, Cappuccino, EZgo, and many others.
Full, safe support for Windows Standby mode including auto shutdown if PC fails to shutdown
Over voltage surge suppression on battery input for protection of harsh automotive environment
User replaceable fuse on battery input to protect your car from internal short circuits
Very compact design measuring 4.6" x 3.25" x 1.75" (L x W x H) or 117mm x 83mm x 45mm.