The curved backplate that
conforms to your leg obviously comes off, but the don't mention how to do
that anywhere in the instructions (and I'm not prying on it). In fact,
their instruction manual tends to be a little lacking with respect to any
of the mechanical aspects of the

They do have an 800 number and will be happy to explain it to you.
I have been using a rail mount in my C172.
Very happy with it.
Hank