It is strange now, that most coils are 11" round and rest elliptical. An 8" round coil used be a standard size with a bigger coil being a 10" round.
I also would like to see detectors having round coils from 8" to 10".
I have never liked the 11" round coils that seems to be the standard now. I don't understand why that is. 8" or 9" round should be the standard.