Includes: FAL Receiver Block (#FALRB), folding stock mechanism (FSM). M4 modular stock (M4M (color), CAR stock adapter (#PN), 1 1/4" ambi sling mount (#UM 1.25) and all hardware needed to install this stock. No modifications to your FAL are necessary. Length of the stock varies from ~ 8" fully collapsed to 11 3/4" fully extended in six3/4" increments. This measurement is taken from the front edge of the CAR stock block to the mid point of the butt. All ACE FAL folding and fixed stock sets require buying and converting your FAL to a "Para" type recoil system, not included, and not currently available through ACE.