New Replacement Air Filter (FILTER ONLY) for use on the OSSA MAR and Explorer models 250/350. TECH NOTE: (YOU WILL NEED TO USE SOME KIND OF WATER PROOF GREESE (EG. BELLRAY) AROUND FILTER TO MADE A NICE AIR TIGHT FIT). MANUFACTOR AND SELLER MAKE NO CLAIMS AS TO THEIR FIT OR FUNCTION. SPECIFICATIONS MADE FROM 30+ YEAR OLD PARTS. FOLLOW UNI-FILTERS RECOMMENDATIONS FOR CARE OF THE FILTER.