I've now used the custom earplugs with my Mach 1 in fixed wing and rotary for a little while, and can confirm it lives up to the promise: No need for the over-the-ear hook any more, just plug it in and adjust the boom, done. Fantastic noise reduction even without ANR, more than good enough for a noisy door-off R22/H300 environment.
3+ hour nav flights, no problem, you don't notice the plugs even at the end of the long flight (standard plugs started to be a bit annoying after that amount of time), and just watch the instructor sweat under his dome headset
