The SLS AMG was designed to be a modern 300SL Gullwing revival by Mark Fetherston from October 2006 to April 2007.The SLS AMG has also adapted the feature of wing doors that swing open upwards on gas struts, and must be closed manually as AMG engineers decided against the 90 pounds (41 kg) that auto-closing systems would have added to the car.[9] In case of a roll-over, the doors can be fully detached to allow the occupants to leave the vehicle