Some Cobra models using the GA-3ANH AAA type batteries won't charge the AAA generic replacements because the charger negative contact is on the outside of the bottom 3/8" of the battery which is plasticized. If you remove some of the plastic wrap with a razor knife the batteries will charge properly and last much longer than the original 300mAh or 600mAh batteries that were supplied with the radio.
The above batteries will have different model numbers on the product pages since they are after market replacement batteries which are as good or better than the originals. The current or mAh (milliamp hour) rating of a battery is an indication of the battery capacity or how long it will last on a charge, the higher the better.
Call toll-free 1-888-966-2299 or e-mail sales@batterycanada.com if you don't see your Cobra model listed.