I use a pair of ancient Sennheiser HD424 "open air" headphones.
To remove some of the highs I use a simple trebble cut, .1uF in series
with a 10K pot, for CW I use a ~.2uf. I have found the open air
phones to be much less fatiguing due to thier much lighter wieght,
and th open design avoids the headach I get form close earphones
like the Koss Pro4As. I also have a 2 strings of 2 each 1N4004's in
series to clip peaks. Crude but effective

Terry