While some newer vehicles may specify a certain type of coolant (like HOAT or OAT), your 1999 Sebring is likely compatible with a standard ethylene glycol-based antifreeze. However, check your owner's manual to be absolutely certain. The manual will specify the recommended coolant type and the proper mixture ratio.
If you can't find your owner's manual, you can often find a digital copy online through the Chrysler website or a reputable automotive parts retailer. Failing that, a local auto parts store employee can assist you based on your vehicle's year, make, and model. They can also provide the correct antifreeze. Don't hesitate to ask for help.