I purchased 2 A20s and love em for the sound reduction qualities.. especially in a 414! However, Bose seems to have an issue with the battery/ANR control as both of mine are broken and they're apparently doing a redesign of them. They gave me the option of sending them back, full refund including shipping, send me loaner Xs or just wait. I grabbed a couple of loaners so I have something to use.

Bose has excellent cust service and a quality aviation product.