This regulated converter takes a 12 Volt to 13.8 Volt DC input via a cigar plug and outputs a selectable DC voltage of 12, 15, 18, 21 or 24 Volts at up to 2.5 Amps.
Originally designed for laptop computers, it can be used with many other items with standard DC coaxial power jack input sockets. Because the output voltage is regulated, this ensures that the item being powered is protected from input voltage changes and surges.
The output coaxial power jack size is chosen by selecting from one of six supplied plugs. These cover the majority of sizes found.

Specifications

Input: 12V - 13.8V DC
Output: 12, 15, 18, 21 or 24V DC 2.5A Max.
Input: Standard Cigarette lighter plug on 160mm lead
Output: Coaxial Power Jack on 1750mm lead