Speed nut, 4.2.

To fit:
911 inc Turbo 1974-1989 Used in the seatbelt assembly, rear interior panels on coupe and the roof frame in cabriolet models
928 1978-1995 - Used in the air conditioning assembly
911 (964) 1989-1994 - Used in the footwell linings, interior equipment, cabriolet top frame, front seat belt
911 (993) 1994-1998 - Used in the seatbelts
911 (997) 2005-2012 - Used in the dashboard and centre console
Boxster (987) 2005-2012 - Used in the upper dashboard
Cayman (987C) 2006-2012 - Used in the upper dashboard