Insert H adds compatibility for the following devices to the current BookArc (2015 and later):
14-inch MacBook Pro (M2, 2023)
13-inch MacBook Pro (M2, 2022)
14-inch MacBook Pro (M1, 2021)
13-inch MacBook Pro (2020)

Insert H 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).