For your consideration are five New Old Stock NOS Autolite AR5S (2243) Waterproof Military Spark Plugs for your vintage M series vehicle. See the pictures for charts to help you derermine if this plug is right for you.

These are getting very difficult to find in new condition, as they have not been manufactured in many many years. My price reflects this rarity. These spark plugs are surplus to my needs, so i am offering them up for sale.