If you have the following car seat, click through to the Safercar.gov press release for more information:
Orbit Baby, Inc. is recalling certain G2 Car Seat Bases, Model No. ORB822000, manufactured from March 20, 2013, through July 20, 2013, with batch numbers A0840, A0860, or A0880. The StrongArm Knob component of the Orbit Baby G2 Car Seat Base intended to secure the seat’s base, may become detached or spin [increasing the risk of injury in the event of a crash].
I highly recommend signing up for recall notifications from the NHTSA here.