THREADED PLUG (CARPET STAY)

Carpeted floor mats in the 360 and F430 (not including Challenge Stradale, Scuderia and 16M) are held in place with a three-part system:  66233100, 66233200 and 66233300.   

The upper and lower rings 66233100 and 66233200 form a grommet in the floor mat itself; they are threaded pieces which screw into each other.    The retaining pin 66233300 screws into the vehicle floorboard and has a slight knob design to firmly grasp the floor mat grommet.  The pieces do break regularly -- order a few and always have a spare nearby!