A/C filter replacement

I bought a used Trailmanor and it had the original A/C filter replaced from material purchased at Lowe's. The unit cools very well but unfortunately often times drips profusely. Any suggestions on filter material that would work well with this unit?

I think the dripping may be a clogged drain on top of the TM itself. I believe the condensation is supposed to be collected in a pan that surrounds the A/C and there is a little drain hole that can occasionally get plugged with debris. If you run tha A/C and don't notice water running off the outside of the TM but it's dripping inside that would be my guess.

I also need to replace my filter - I also have the original and it's in pretty rough shape from repeated cleaning.

Regards,

Bob