Upvote:1
AFAIK.
You only need a couple of adapters,
I've never been in a situation where I would need a volume limiter so I cannot comment on its usefulness.
I'm not certain you need much more than that;
I've not seen anything else in my 30+ years of travel (mostly between western Europe and America).
Personally, I only carry a mono-mono adapter and a cheap pair of earphones (3.5mm) to connect to the plane entertainment system and a pair of Bluetooth in-ear headphones to use with my phone.