BookArc - Insert C

Insert C adds compatibility for the following devices to the current BookArc (2015 and later): 12-inch MacBook Insert C is not compatible with BookArc mod, BookArc for MacBook Air (pre-2015) or the previous version of BookArc for MacBook (pre-2015). Not sure which BookArc you have? Previous versions came with numbered inserts (1-8) while the current BookArc has lettered inserts (A-H).