I decided to replace the air filter because it had been over 2km, but I saw that it had just been released so I bought it.
It's reinforced with stun mesh, so it doesn't seem to be deformed by air intake, so there were no problems with the fit.
It's a shame that it can't be washed and reused because it's not wet cotton, but it's a dry type that uses non-woven fabric, which seems to reduce intake resistance.

●Hyogo Prefecture Cello (CX-60/KH)