For the 2007, 2008, 2009 and 2010 model years, the factory keyless entry systems for Hyundai Elantra used a 4-button keyfob with FCC ID OSLOKA-310T on the back of the case. Lock, unlock and trunk buttons are on the front of the remote and the panic button is on the back. Here is a link for the part.
The exception to this usage is that the Elantra Touring models from 2008 on had a liftgate rather than a trunk and used a different keyless entry remote. All of the Hyundai remotes during this period require dealership programming with a scan tool.