I have used the www.hamstick.com
economy dual-band whip on a 3" mag mount with fine results. I keep this one at work when I want to monitor amateur radio in the County vehicle which is not so-equipped. The antenna is the 18" cellular look-alike with the "pigtail squiggle." It is only unity gain, but VERY broad banded. VSWR is 1.5:1 or less across the entire 2 meter band, and 2:1 or less across the entire 440 amateur band. It is also entirely "useable" at 2:1 or less on the high-band VHF business band and VHF marine band as well as the 450-470 Mhz. business and public safety bands and GMRS. As a one-size fits all spare mobile antenna for your "Go Kit", it's pretty hard to beat.