One is one year old and includes the allen wrench to tighten to seatbelt, the other is 4-5 years old and does not have an allen wrench (I'm sure most of us have one that will fit kicking around somewhere).
How it works and some info can be viewed here:
http://www.soloperformance.com/CG-LOCK_ ... 4Aod93sA4w
They sell new for $55-60. The old one I'd let go for $30, the newer one $40
Old One:
![Image](http://i1176.photobucket.com/albums/x335/Emveeii/photo_zps592f2aec.jpg)
New One:
![Image](http://i1176.photobucket.com/albums/x335/Emveeii/photo1_zps187ffb97.jpg)