SPORTY's sells the specific Cessna adaptor.
http://www.sportys.com/acb/showdetl....ID=9591&DID=19
Now you can plug your handheld GPS into your new Cessna's electrical
system with this handy adapter. Simply insert the small end of the
connector into the airplane's 12 volt cabin power outlet, then plug your
GPS, radio or laptop into the female cigarette adapter end. The adapter
weighs almost nothing, but will stand up to almost any abuse. Measures 8
1/2 in. long.
Ordering Information
12V Cabin Power Connector
Item Number: 7826A
Price: $19.95