You’re going to have to get some more specifics from your airline. Even with that, though, sometimes you get screwed and have the seat with a little less clearance than they publish.
Personal items typically fit under the seat in front of you, so you can look for “underseat carry on bag” to get a rough idea of what is available.
As an added bonus if you are in the very front seat and they say to put it under the seat in front of you, you have no where to put it
Personal experience when I went to DC.
Why not under your own seat…logic dictates everyone gets their own seat, not everyone has a seat in front of them.
I bought this guy cause it’s smaller and soft sided. And no wheels because I’m not a loser.
https://www.awaytravel.com/travel-bags/outdoor-convertible-backpack-45l
no wheels because I’m not a loser
Your ancestors must be rolling in their graves… without wheels.
luggage should glide across the floor
Statements made by the utterly deranged