Think Outside Stowaway Universal Bluetooth Keyboard - Manual (Page 11)

Page 11
Assigning Applications to Fn Keys
There are two options for what applications launch when using the
Left Fn key in combination with Home Row keys (for Stowaway users
this applies to the function keys on the far right side of the keyboard in
combination with the Fn key).
Simulate Buttons
This is the default setting and will
launch the applications/functions
that correspond with the printing
on the keys.
Configurable
This allows the user to select the
applications/functions that are
launched. For each key there is a
drop down list of all the
applications/functions currently
installed.