I know there is a write up on using the bottom from a can to install a new filter in the MZ Country since there are no specific filters available. Being a plumber, I put my spin on the conversion. I used an old plastic paper box and drilled a 4" round hole in the back. I put the round disk that I drilled out in a vise to hold it and drilled a 2" hole in the 4" piece. Then using the original round metal center piece from the old filter, I put it all together and tightened it up. Her are a few pics. I used a BMW part number 13 72 1 342 355